I'm in the Dallas area and went with a local company, Don Young Windows. Their website does a nice job explaining thermal breaks and how it works so even if these aren't available to you you may find their website helpful. When comparing windows I had to really dig to find how much gap was between the panes. You may want to look at that as there were some significant variances. I'll look for the info for the vinyl company I looked at and if I find it I'll post the name because they were a better quality vinyl brand.

Updating this thread for others considering aluminum frames: We did install the Milgard aluminum windows. They are really neat looking! My one regret is that there are a few windows where the old had a fixed pane and a casement. I ordered double casements instead, and probably should have stayed with the original layout. This because the double casements have a lot more 'frame' showing than we originally had. A few other things: 1.) We had some problems making casements work in some bedroom locations - due to emergency egress requirements. Basically a Milgard casement must be 30" wide for egress. Narrower and it won't meet code - even though the hinges are on the jamb. Wider and it becomes too heavy to work right. So we had to use sliders instead. 2.) Energy-wise, Milgard offers 'thermally broken' aluminum frames, but, strangely, not in California. I did order our windows with Milgards "Suncoat Max" upgrade though. It is interesting to place ones hand on the frame and then place it on the glass. Big difference in temperature. However, combined with other things in the construction (e.g., IB Systems membrane roof, and Techshield radiant barrier decking), the house is staying suprisingly cool during the current heat wave. (Got up to 100° yesterday.) And the insulation and drywall have yet to be installed! So in our case the aluminum frames don't seem to be a big problem. But if one were to insist on thermally broken aluminum, then Fleetwood seems to be a better way to go. (FWIW, I gave the local Milgard area rep a hard time about not being able to order thermally broken in California. Seems silly that you can order them in other states, but not here.) 3.) Milgard delivery was *fast*. Like less than two weeks from order to delivery. 4.) A nit: Our frames are dark bronze color, almost black. For some reason the screws mounting the casement lock handles are bright colored. Yet other screws, such as the ones holding the screens, are black. I need to call Milgard to see if they can provide some black screws to make the bright ones 'disappear'. 5.) For the master bath, I ordered reeded obscure glass, on the thought that it kinda carried the theme of the reeded obscure glass in the sidelight of my front door. (Of course a workman accidently broke the original 1950s sidelight a couple weeks ago, so now I get to match the sidelight with the master bath instead...)

Good info here. I have been shopping Pella, Marvin, JenWeld, LLuminare and Softlite. The quotes are all over the place- or not coming in at all ?? This is what I need: new construction 46 windows, many "fixed" /picture windows, rest are casement, slider, horizontal slider, awning. Looking for contemporary/ modern look with black or dark aluminum exterior and black interior aluminum clad - frameless, mounted with a drywall wrap look and adding some ornamental sills later in specific rooms. Appreciate any advice for vendors in GEORGIA. ( house is in 30522 zipcode)

I did give that a bit of thought, lovemrmewey when I decided to give up the first floor bedroom to add more living space in the kitchen area for today. If need be, I can reconfigure another area of the first floor for a small bedroom if one is required in the future. For now...I am holding a vision that I will be healthy and able to manage stairs to an upstairs bedroom. Both floors will now have bathing/showering options. In the past, that was only on the first floor.