We replaced all of our aluminium, single pane, sliding windows in our 1967 ranch style house.  We chose Simonton for their appearance, price and value, after shopping big box stores, and 3 other replacement companys.  Simonton was the best, hands down. Relacing our windows was the single best improvement we've made to our home.  The windows operate smoothly, fit perfectly and do a wonderful job of keeping out noise, drafts and heat transfer.  I like the lifetime replacement guarantee.