I worked in the replacement window business for over 10 years. I sold OMNI by Alside for 6 of those years. Triple glazed double low-e and argon filled. They were good windows not great, because the heavy vinyl frames were not welded. The still were guranteed to reduce energy use by 40% in writing. Never had a customer complain. The devil was in the details. If any window is not installed correctly, you might as well not spend the money to start with. That company stopped making that brand and the dealer I was working for had to find a new product.
He found these.
http://www.uniframewindow.com/
They were even better. I am currently replacing all my windows, one at a time with them. Triple glazed, double Low-e and Krypton filled. Like I said installation is critical.
Our company pulled 1000's of wooden windows out. Anderson, Pella, Eagle, Marvin. The big reason is that they are all wood with vinyl or metal cladding on the exterior. Moisture gets behind the clading and warmth, moisture and darkness spell mold and mildew and that means rot and most of them now are made not with solid continuous frame pieces but finger jointed glued up sections which as you know as wood workers. A joint even the best is less than solid wood.
The one brand to stay clear of for sure is the Pella Pro Line sold through big box stores for DIY'ers. There are some good vinyl windows sold at Big Box stores, but not many. Look for foam filled cores with steel or fiberglass reinforcing beams running through the inside of each frame member.
Pay particular attention to the meeting rail where the two sashes meet. There needs to be a deep interlock so and double or quadruple pile insulation.
I wish I could show you the 100's of windows (vinyl replacement too) that we pulled out to find that the big problem was they were sloppily installed.
I have even pulled out Schuco Vinyl (German Made, Heaviest in the industry) and reinstalled them for the customer the correct way and solved the problem. We only got paid for labor on that job but, left a happy customer that sent us tons of referals.
The company you deal with in that industry is everything. There are a ton of fly by nighters who operate out of the back of their pickups and your warranty lasts until his tail lights pass the stop sign at the end of the street.
They company I worked for in Iowa has a 100% customer satisfaction rating with the BBB in Iowa. They have been in the business 50+ years.
Since windows are are so important to the integrity of your house. You need to do your home work and don't listen to TV Ads. Pella and Anderson have huge advertising budgets. Problem is here in Iowa they are sold through lumber yards and they yards don't install. Most carpenters can install good new construction windows. Some can even do a good job on replacement windows.
Price should not be the determining factor.
Price - Service - Quality. Pick two.
You cant' bet both with out paying for it.
OK, I am done with the soap box now. Next!!!