We chose to install Serious high performance windows.  To be hard-core we would’ve bought German windows but we’re not hard-core.  We’re medium core.  Serious windows are made here in the good old USA.  They’re not a household name unless you’re building a seriously efficient house like we are.  To keep our budget in check we went with their middle of the road 525 series windows.  They’re decent looking windows although not aesthetic standouts by any means.  They’ll do the job.  We chose primarily casement windows as casements will net better performance than double hung.  Many of our windows are fixed which are even better.  Only problems we’ve run into revolve around our ability to order properly and issues with the expansion balloons.  No one told me about the balloons so we waited longer than the 5 days to crimp the tubes and cut off the balloons.  We were told this shouldn’t be a problem.  What is a problem is one balloon got sliced by a worker and was in the upside down position so for all intents and purposes I have to assume all the argon gas escaped.  We’ll get a Serious tech out to fix that window.  Additionally we had one window miss sized by the architect and two miss sized by the manufacturer.  I contributed by miss ordering 4 windows that needed to be tempered and they weren’t.  Finally today I noticed I forgot to order one of the garage windows.  So a bad start but at least they’re going in.