Where are u located? I can tell you with confidence, all 3 are excellent windows.

scot, all of that info is indeed available, however you unfortunately will not find one easy source with all of the info. Okna and Himark have all of the relevant energy numbers (u-factor, air leakage, design pressure, etc) posted right on their website. If you want verifiable data rather than just trusting the pros that post here, you can get all of the thermal data from NFRC.org. For Structural data (Air leakage, dp, etc), you can request a structural data test report from each manufacturer (or from one of their dealers, as some manufacturers won't deal directly with consumers). On STC, that is something that you'll need to get in that manner as well.
I'd confirm mmarsel's sentiments, that those are indeed elite choices that you are considering. Best of luck in you research, please feel free to post back with additional questions.

Scot,

STC is a tougher one as the testing for it is very specific and resultantly expensive.

There are some good sites for sound attenuation and no double pane window (without some specialty glazing in either offset or laminated) will approach a 35 rating.

What are the noise concerns and how much blocking do you need to do?

http://www.stcratings.com/

Here is a link that might be useful: STC Ratings

WoW: I haven't been able to give you all a call back today, but appreciate the help here too. Looking at a place near ashburn, so Dulles airport noise plus a nearby park.

I like real silence in my house, and while I'm never going to get that if a plane is flying overhead, I want to get it close. I was thinking about STC around 35 as a realistic and semi-affordable option, hence laminated glass in a good dual pane window setup. More than that seems extremely expensive.

BTW, to everyone else. Well aware these are top quality. Much like ferrari vs lambo vs aston martin, they are all great vehicles, but suited to different purposes. Gotta know the details to figure out which is right :)

Scot,

No worries. I didn't even know you were in our area.

We are here whenever you are ready to chat and if you call, ask for Eric and tell them I told you to.

As WoW said, not all manufacturers have their windows specifically tested for STC ratings, so that may be a hard number to get firm on.

As to noise reduction, insulating the perimeter of windows with minimal expanding foam (rather than simply caulking them in) will have an impact.

Some manufacturers will alter the glass, to say âÂÂ" over 3/16" to give you slightly better noise blocking and it's typically not a big up charge.

You can't do better than Windows on Washington in the DC area. Great guy, top end products and professional installation.