I know I'm a newbie here but I wanted to post my experiences with these two red dot optics.  Both were mounted to a SAR-2.  Here are my opinions:
PK-AS pluses--can be operated with dead batteries due to permanent "black dot" feature; small, compact design; dot doesn't "wash out" on bright backgrounds due to the black dot feature; can use open sights as the mount sits to the left; rapid target aquisition; good hold of zero; rugged construction.
Minuses--sighting in a little more tedious as you need a hex tool to adjust windage & elevation (included with scope), windage adjustments can only be completed by removing the receiver cover when scope is mounted via side rail.

PK-AV pluses--adjustable brightness of the red dot; windage & elevation knobs easy to use & adjust; rugged construction; rapid target aquisition; good hold of zero; price under $200 from internet vendors.
Minuses--washout of the red dot on red backgrounds (ie--don't use red or orange targets); inoperable if batteries die & mounting of scope makes open sights more difficult to use

Overall--both are nice optics that live up to what's advertised. Both allow two-eye aiming and hold zero well. I have to give the nod to the PK-AS as I really like the operability of the scope regardless of battery power. As far as value is concerned, I'm a big fan of the PK-AV as I think you get a lot for your money ($179 from one internet vendor).  Both compliment the AK quite nicely.  I'm going to keep the AS on my SAR-2 & mount the AV to my WASR.  Shooting at active targets on an action firing range with these scopes is a blast & hitting vital target areas is no longer an exercise in frustration!

p.s.--I am not affiliated with any vendor offering these optics. I just wanted to give a shooter's opinion of both since I've found so much of the info shared on this website helpful.

Thanks!  The PK-AS also has adjustable brightness of the red dot.  However, I think this feature is more "user-friendly" on the AV than the AS (the brightness knob is easier to operate).
I agree, for the money, both are a hell of a deal when compared to the price of an Aimpoint.  There is also something cool about mounting a Russian red dot (country of manufacturer is actually Belarus) on an AK.  Kind of like pairing pizza & beer instead of pizza & wine or some other libation...

I just got done sighting in my PK-AS on my converted Saiga (5.56).  Just so you know my perspective, I am a left handed shooter so my perspective is going to be different than a Right Handed shooter since the sight hangs off the left side of the weapon.  

Gun           Saiga (converted)
chamber    5.56x45
Optic          PK-AS
Ammo        Olympic 5.56 (62 grain NATO spec) and Wolf 5.56 (55 grain)
Weather     Nice day, 70F degrees, no wind, dusk sun
Conditions  Bench-Rest rifle range with sandbags

I bought my sight from www.freedomoptics.com I want to say this because the gentleman who runs this site has excellent customer service and quality product.  I am NOT affialited with him and I am not getting a discount (I wish I was) but my experience with him was great!!!  This site has a good English translation of the PK-AS manual as the PK-AS comes with a manual in Russian only (complete with Stamps - if you have ever been to Russia or dealt with Russian official documents, you will know what I mean).  I recommend going to the sight to get the English translation before you begin to sight in the PK-AS.

The PK AS is an intimidating looking sight.  I was impressed just by the looks.  It just looks great on an AK.  

BUT

The PK-AS is a BEAR to sight in.  I had to make 2 trips to the range to sight it in (because I forgot the English translation to the book) but we finally got it sighted in today.  You have to make your shots, remove the sight, loosen the locking screw, make adjustments, tighen the locking screw, re-attach the sight, shoot again, repeat.  This is extraordinarily teadeous and we were using a spotting scope so we didn't have to walk so much.  The attachment clamp is not hard to operate but it is still a pain to have to remove the sight to make adjustments.

BUT

Once we had that PK-AS sighted in, I was able to hammer nails with it.  We shot from the bench rest and were having great results.  After this, I stood up from the bench and was taking shots at a 2 inch plate of steel (1 foot squared diameter painted red) at 100 yards and hit the target every single time.  The adjustable red-dot is great because you can make adjustments to your preferences or for the background you are shooting at.  I am a left-handed shooter and the over-hang of the sight to the left of the rifle gave me a great cheek-weld to the butt-stock.  Target acqusition was very quick and I was able to see what I was shooting at a lot better than using the iron sights on the AK.  

conclusion

If you own an AK, I recommend that you buy an optic for your rifle.  For such a small investment, improves the rifle significantly.  The PK-AS improved the rifle's accuracy and in my opinion, made the rifle a better weapon.  I have shot an SAR-2 with a Kobra and I am not slamming the Kobra.  It is a godo sight also.  The PK-AS just looks good and shoots great.  I own and shoot an AR-15 and I shot an M1A this evening after sighting in my Saiga today and I feel that you can get good accuracy from iron sights with these peep sights.  With an AK using iron sights, I can't get such results.  With a PK-AS optic, I can easily get this accuracy.  

In the end, even though it was a pain to sight in, I say it was worth it.  You don't need to sight in the PK-AS all the time so I am willing to forgive the pain-in-the-ass sighting in process.  The results were worth it.  

I bought my sight from www.freedomoptics.com I want to say this because the gentleman who runs this site has excellent customer service and quality product.  I am NOT affialited with him and I am not getting a discount (I wish I was) but my experience with him was great!!!  This site has a good English translation of the PK-AS manual as the PK-AS comes with a manual in Russian only (complete with Stamps - if you have ever been to Russia or dealt with Russian official documents, you will know what I mean).  I recommend going to the sight to get the English translation before you begin to sight in the PK-AS.

Yuri at FreedomOptics is absolutely awesome to deal with...they will definitely get more of my business in the future...

...sorry if am side tracking the thread but wanted to chime in and agree with what efaust93 had stated...

I prefer the older, original PK-AS with the non-variable brightness on-off toggle (KISS principle). I find the toggle easier/quicker to use than the variable control plus I don't find myself tempted to play with the dot's brightness trying to make it "just right". I like that the sight is operable should the batteries/electronics fail if ambient light is bright enough. I also like that the irons are always instantly available for use and that I can remove the receiver cover for cleaning w/o removing the PK-AS first. Yes, sighting it in is tedious! But, you should only have to do that once and then it's amazingly rugged (I accidentally dropped one of my PK-AS sights about 4.5' onto concrete w/o damage or losing zero). Today I sighted in a new SEAK w/a PK-AS and after initial sight-in I placed 10 bowling pins in a 90 degree arc from 10yds to 25yds out. I then loaded up a single 30rd mag and ran a quick acquisition/fire drill 3 times. Final score: 30 shots fired, 30 pins down. This was done w/o illuminating the dot (bright Idaho sunshine, nearly washes out the illuminated dot anyway).
Tomac

Can any of the PK-AS owners explain how the optic handles parallax?  Traditional red-dot sights are free of parallax past 50 yards or so, but I don't see how this is possible with a reticle that is etched in the glass.

Quoted: Can any of the PK-AS owners explain how the optic handles parallax?  Traditional red-dot sights are free of parallax past 50 yards or so, but I don't see how this is possible with a reticle that is etched in the glass.

I don't worry about parallax w/the PK-AS. It's primarily a CQB sight where parallax isn't an issue at closer ranges. While it can be used quite successfully at longer ranges (I've gotten hits on the 400m gong), this is generally slow, aimed fire where one can take the time to keep your eye centered behind the sight which effectively eliminates parallax.
Tomac

I have a PK-AV on my SAR3.  I like it.  It was a bit confusing to sight in due to the Russian markings.  I found that I needed to set the intensity at the highest level in bright sunlight.  It mounts without offset and at what think is a perfect height - high enough to use the iron sights with the scope mounted but low enough to be comfortable to shoot.  The dot seemed rather large - covered about a 4" diameter circle at 100 yards.  I was a bit disapointed with it as I was shooting - with my SAR3, I wasn't able to shoot any better than I do with iron sights.  But the SAR3 is exceptionally accurate for an AK.  After the AWB sunset, I'm going to put it on an SA85M with a side folder.  I think the red dot is better suited to a folding stock rifle since it makes the difficulty to get a proper cheekweld irrevelant.  I also think the dot sight will be better suited to the accuracy of the 7.62 round.
Overall, I'd recommend the PK-AV.  It does what it's intended to do, it's a very rugged piece of kit and it looks right on the weapon.  I got mine through Freedom Optics, great source.  Yuri was very helpful when I was researching the whole PK-AS/PK-AV/Kobra thing.