Whatever you do, don't buy Pella windows. I have two reasons why you shouldn't. First, a friend in the business. Second, personal experience.
I did not buy Pella windows. They came with the house that we bought last November. The problem that I'm having is two-fold and deals with a sliding glass patio door with a retractable screen. First, water leaks through the frame of the door. Second, the retractable screen is missing the part that hold the screen so that it can be pulled out.
A friend of mine works for his family business, Savocchi Glass, Window & Door Company. He says that servicing Pella windows and products is difficult.
It seems as though the manufacturer makes it difficult because they have their own service people. Therefore, they probably make the products so that they do not take universal parts. They also probably make it difficult to obtain repair procedure manuals. These assumptions are made based on my experience in the auto repair business, where car manufacturers make it difficult to get repair procedures, though they do sell parts over-the-counter.
The second reason for my warning against Pella products is that the service is difficult to come by and the manufacturer is disorganized. My experience, though not complete has been the following. I called to get an appointment and the soonest was approximately three weeks out. They asked me to send pictures of the product in question so that they could send the appropriate parts with the technician. When the technician arrived, he found that one of the parts needed to repair the problem was not properly packaged with the set. He said that such was not uncommon. He also asked if he could leave the correct parts in our garage, as he said that it would be likely the box would come up missing in the time it would take to order the misboxed part. Such statements do not give me the feeling that such a company would be worth doing business with.
They seem to be the type of company who is good at getting their product name out and onto store shelves, but are bad at servicing their products. If I were buying new windows and did not already have a connection, I would definitely read reviews and talk to several independent window installers to get an idea of which products are good to purchase, install, maintain, and repair. As much as we do not like to think about it, all things break and will need to be serviced. You want to have a product that is serviceable.