Apologize if this has been talked about before. We pig hunt. A lot. Been stumbling around in the dark for a long time. Spent money on thermal first. Like to pick up some i2, for no stumbling purposes. Have read until my eyes bleed. But still not sure what's really gonna suit us best for the money. Have talked to several different outfits that sell it, and the usually recommend their best stuff. I'm ok with spending the money if it's really worth it and will last. Obviously gen 3 is always recommended,but if I can spend less o gen 2, and work for us that's fine. I don't want to own the best so I can say I do, I want to own what I need. I've looked at the write up tnvc did on this site comparing several different situations.  Was helpful , but at the end of the day I'm not worried about being in a building or street lights etc. it's always dark. I'd like to. E able to navigate, mostly by foot at night, when it's really dark. So based on all that what is recommended by anyone whose in same boat?  I'd like the following things
1. Quality.  I take care of my gear but it's not babied. Warranty included in this category
2 specs. Not sure what I need here. I get higher is better, but again ,not try to determine difference in Mbl phone and pistol.
3 single vs dual tube set up. Have read that dual provides better depth perception, and it makes sense.  But it it so much better that it worth the price increase. Again, we shoot with thermal, so navigation only
4. External illumination. Very dark almost always mostly open pasture but ocassional thicket. In my brain some sort of adjustable light would be most efficient. Something that goes from flood to focused beam.  Not sure if that exists or not?

Any suggestions are appreciated. Will be buying several complete set ups so would like to get it right the first time.  Thanks for any help you can offer

Also worth mentioning that I've read gen 2 useful life is less than half of gen 3. Is that accurate?  If so that's a no brainer for longevity

Yes.

Some Gen 2+ NODs has a 10k tube thats Autogated and is very very clear where it lacks compared to a newer Gen3 unit is when you are in a very very dark building, under a very thick canopy or under a no moon/star lite night with no city lights around. Keep in mind not all gen 2 or 3 are created equal. Some Gen2 can out perform early gen3 units. For navigation only a TNVC hand held with an adjustable beam may serve you well but of your looking for a fixed beam a Solar Force IR bulb and flashlight for 25.00 is hard to beat for hunting. If you ever to hunt with NV a pvs14 monocular is more universal since it can be head or weapons mounted. I navigate fine with a pvs14. As with all NV using it often is the key till it becomes second nature to you.

Yes sir a an education is what I need. Would like to talk

For hunters, I would check out the NGI PVS-14 line.  They have some really nice gen II/gen II+ stuff in -14 housings, which would give a hunter a good set of decent NV gear for around 2K.  Combine that with a good IR illum of your choice and you'd have a nice hunting set-up.  If you helmet mount the MNVD and get a 1/2"riser for your rifle mounted RDS, you can actually kill a bunch of critters by still using the RDS reticle.  Since you already have the -14 housing it would be a simple matter of up-grading to a gen III tube later if you wanted.

You'll get all sorts of answers here because guys have all sorts of different uses, wants, desires, etc.  But since you are pretty locked into your mission, I think NGI is a nice sweet spot for your needs.

Thank for replies so far. Having trouble responding to msgs for reason. Sorry not being rude. Offers are appreciated...

Its mostly a misunderstood metric. Fwiw i have many 30 year old gen 2 ststems that work just fine to this day. The original number was based on snr loss on pvs5s going from 12 to about 9 after which they were no longer deemed good enough to work under starlight conditions.

Which is yet another reason that I see the need for some new evaluation criteria. The technology has evolved very far in the past 20 years and we find ourselves getting into a lot of apples and oranges arguments.

Yup...

I think there is enough experience right here on this board to do a number or lettering system to see how devices stack up against each other, versus the mil/gen designation.

Honestly probably the best thing to do is to consider resolution and SNR, as many people here suggest. PC is also useful but with the understanding that the Ion barrier film of most gen3 devices rejects anywhere from 60-30% of the electrons generated by the PC and the rejection rate is pretty hard to quantify.

There is also the following caveat. Early US gen2 SNR numbers that are published are using a very old test method that was later revised, so if you see something with an SNR of 4, it would be ~12 on the new system. This mainly applies to MX9964 and MX9916 tubes (PVS4/5). The other "Fun" fact from that era is that 9916's improved over time, but the specs were never really upgraded. So 9916's in later model PVS-5B's and C's are somewhat better than what the original 70's era spec would suggest in terms of resolution, SNR and PCR. Modern Gen2+ (or whatever you want to call it) from photnis works significantly better than stuff from the 70's.

The other issue with comparing traditional gen2 and 3 devices is the spectral range where they work best. Gen2 works best in "Visible" light range, while Gen3 works best with near IR. So... Given that moonlight is basically reflected sunlight, and it dominates the night sky spectrum when its available (25/30 days in a month ish), Gen2 works great. When its down to starlight Gen2 devices struggle due to less overall gain when compared to gen3, and spectral mismatch. Gen3 happens to work very well with the IR light that is available on moonless nights.

The published omni chart here applies to 10160 grade tubes, but is in the ballpark for other tubes of the same era, usually those are a bit worse spec wise tho.

My mantra has been that even old school mx9916's are good enough for most of the things civilians actually end up using NV for. If its too dark, you just turn on the illumination. By the time you get to Omni4 or better tubes, its IMO a point of diminishing returns unless you are kicking doors for a living. And I fully understand that there are some arfcommers that think they need that capability, so they go out and pay for it. So its just my opinion man...

Have been gone for a while. Thanks for the help. Still haven't decided which route to go  . So far up with a couple more questions ....  
1. If I did go with the cheaper gen 2 could the tubes themselves be upgraded at later date? Seems like it, but haven't gotten straight answer
2 what would that cost? For the labor, understand tues cost what they cost and it varies
3 why is warranty so much different between 2/3?  Seen 5-10 years on gen 3 but only 2ish years on gen 2
4 why no spec sheets offered w gen 2 products ? Guess it doesn't really mater, just seems odd since some make a big deal in advertising you get the spec sheets when you buy there top of the line equip

1. It depends, generally if you are going with a PVS-14 type system with a Gen2 MX10160 style tube then the answer is YES. If its some older MX9916 based system, then the answer is maybe, but it won't be cheap.
2. Swapping tubes is something you can do yourself its not really hard. I have no idea what ppl might charge 100 bucks including a purge?
3. No idea, where are you getting that data? Could the gen2 tubes be russian (known for less than stellar power supplies).
4. No idea. I have spec sheets for 2 of my tubes, I don't think its a big deal at all to have one.