ok - maybe I'm in the wrong place
We had a small window installation company that told us outright that they are competitively priced (not the cheapest), and they wouldn't even give us a volume discount if we did more windows. This is a sign that they were not out to make a quick sale with cheap installation.
They mentioned 2 main types of window replacement:
1) Retrofit, where they install the windows in the existing frames (actually making the new window installation a bit smaller and suseptable to air leaks)
2) Brick to brick, where they gutted the entire window frame and re-built it.
They said brick to brick would allow them to properly insulate and lay out the window - and do it right. It cost a bit more but it was worth it. For our upstairs windows that were terrrible from the original builder 10 years ago, we've done all the windows over the last 3 years.
Definitely, get references from friends, but if you find an installer that 'teaches' you something about installation before just doing it or pushing it, you probably have made a right choice.