Hi,
I'm a newbie in the market for a handgun.  Can someone give me their opinion on the P99?  I understand it is double action only with "quick action".  How is this feature?  Any downside?
What websites have the best prices?
I'm also considering the CZ 75 B, Beretta PX4, and Sig 226.

Actually, the P99 is not necessarily only DAO (double action only), and the "quick action" (QA), is different from the DAO.  The P99 comes in three different trigger setups.  The first is AS (Anti Stress).  This is what I have, and gives you a single action for quick follow up shots, but also offers the ability to decock and have a double action first shot.  Since there is no safety on the P99, I find this a nice feature.  First shot is a bit harder to place accurately, but after that, it's smooth sailing.  The second trigger setup is the DAO.  This is basically the same as the AS for the first shot, except every shot remains in DA.  This basically allows for a consistent pull to the trigger, without the difference between the first and second shots.  Finally, there is the QA, which I don't completely understand because I have not seen one.  But, from the Walther catalog "Partially preloaded striker provides a uniform short light trigger pull."  

As far as the P99 in general goes, excellent firearm, I highly recommend it.  I have NEVER had a FTF or a jam with either of mine.  The first one had almost 10,000 rounds through it, and this one I currently have has around 5,000.  The only downside of the gun that I've been able to find is holsters.  There are many holsters that work great for it, but many of the manufacturers do not list the P99 on their holster line-up.  Typically, you have to either find the Smith and Wesson SW99 or the HK .40 USP.  A holster that fits either of those is most likely to fit the P99.  

Blackboot.

I have 2, a standard P99 and a P99 compact, both are 9mm and AS triggers/with decocker. As Mac said, AS=D/A S/A.      I  got, and qualified the P99C for CCW. Both are nice shooters, narrow, and some what light. I've got about 3K rounds through the standard P99, with different mag's and ammo with no problems. Both P99's share magazines, holsters, and the standard 4"barrel fits the 3.5"compact slide.  I bought my compact at CDNN back in December.

The P99 is a great pistol I have 3 in 9mm.
The AS trigger is like a DA/SA but, when you load a round the trigger goes to the DA position, but has a light take up back to the SA position. If you use the decocker the trigger goes to the DA position and has the heavier DA pull.
QA is a preloaded striker like a Glock trigger, same pull every time.
P990 is DAO, longer and heavier pull every time.
Af as websites, www.cdnninvestments.com(have to download their PDF) had some good prices but they might be out.
Buds Gun Shop
AK-47man
Keep in mind that Walther changed the styling of the P99 post 2004, so finding a holster may be a problem depending on which version you buy.
Walther FAQ

Thanks for the info!
It's been a great help!