I had a horrible experience with Retroteck on multiple levels.
When the windows showed up to be installed, they were not as specified when the order was put in. Upon further inquiry, Retroteck told us that our windows were too small for wicket boxes (the missing feature). Yet, they had come to measure our windows three separate times, and we had never been told that the product we ordered (on their advice) and paid for in advance in full was not compatible with our window dimensions. We never got a partial refund, despite getting a product lesser than that ordered. Furthermore, without the wicket boxes we had specified, opening and closing the windows involves removing the screen. On all the windows. Every single time. Which isn't even easy.
Their "customer responsibility sheet" indemnifies them from pretty much any damage they cause during the installation process. The salesman told us that it would be merely "some inevitable scratches on the wall around the windows," which we thought was fine. In actuality, our literally brand new tiles below the windows were broken in multiple areas, and the paint on the walls around the windows were left cracked and peeling, along with some of the grout. When they left, there was garbage (nails, screws, broken glass, sealant, etc) left strewn all over our yard and garden.
When I initially tried to contact Retroteck about these concerns, Peter at the office finally picked up (after multiple days and messages left) and was rude and shrugged me off, hanging up on me. Communication with George (the original salesman who recommended the incompatible window design that we ordered instead of a simpler design that would have worked) yielded similar results. Evidently, they've been paid, and since windows last a pretty long time, they don't care about past customers because they don't need repeat customers.
Retroteck's windows themselves are actually pretty good, but we did not get the product we paid for, and the installation and customer service were all abysmal in my experience. I would not recommend them to anyone.
22 Feb 2015 update: After I lodged a complaint with the BBB, Retrotek came and modified the windows to meet the original specs. We are happy with the product now.