Highly recommend them. I love my new windows. They installed low-e windows in my house about a year ago and it was one of the best improvements I've made. The product is high quality, and warranteed for life. I had one crack on me - a quick phone call and a new sash was on my doorstep 2 days later.
They were very clean and professional. Start to finish was 2 1/2 hours, tops, for 10 windows.