We're building a p & b with Foard panels and the custom window guys I've spoken to (and cannot afford) have recommended Loewen windows. Their standard window is doug fir and they are beautiful. Also, the quotes I've gotten for the double hungs and casements are less than if you bought Marvins - which suprised me. Finally, they make their glass, I believe, which means that instead of having a small pin hole where the argon goes in, they put the gas in during the manufacturing vertical process (?) which means the gas doesn't leak out. I've been told not to bother with the Argon otherwise because it does eventually leak out of other windows. They are trying to build windows for generations, not just for 20-25 years, and a panel company owner I know installed them in his own house.
Just an FYI - doing the same research right now.