We looked at several window companies, we narrowed it down to 3; we had them come to our home for an in-depth interview (not sales...interview, because we were asking all the questions!) After checking multiple sources, we were impressed with the quality of the sliding glass door by Polar Seal. We contacted them to give them the go-ahead and they scheduled a date and time for someone to come out to take measurements. The wonderful thing about Polar Seal is they build your door/window to your exact dimensions. This is quite different from buying something from stock and having the installer fit it in with shims and foam. Another plus, is that these doors are made to your specifications, right here in Michigan! The installers came right on time on the date scheduled and before doing anything, they verified the measurements!. Once they were satisfied, they began removing the existing door. As a woman, I was particularly pleased as I watched one man cutting through the existing nails/screws/etc, while on the inside of the house, the other gentleman was holding the wand from a wet vac, sucking up all dust and particles from the removal, keeping my house clean!!! They took a great deal of time making sure everything was perfectly installed, and any little item was addressed immediately. When they were done, the work area was spotless. The door itself: The quality of this door is amazing. It's sturdy, strong, very well made. There's a double lock on the glass door, which is something I've never seen, and there's a safety "dead bolt" at the bottom left corner of the sliding door. This provides an unobtrusive second layer of security, which is well designed and easy to use. The frame of the slider is very sturdy; it's a heavier weight polymer vinyl that doesn't bend or move when you try to force it. For example, there are windows you see on display at stores, and the vinyl lip of the channel can be moved out if you push on it; not this. This is tough stuff, and along the bottom track are drainage holes so that water doesn't collect and damage the door. Our original door was wood, and it did not have the drain holes; there was rot because of that. The stationary window is very sturdy; the screen has a handle that has a special design. It isn't the typical plastic one piece screen handle. This design has you using two fingers to guide the screen in place. This keeps the screen from bending over time. The sliding glass door is sturdy, strong and very nice looking. All in all, I'm extremely pleased with every aspect of our interaction with Polar Seal. This company has been in business for over 50 years for good reason. In the next 2 years we're facing the replacement of our living room windows. These windows create the whole wall, plus windows on either end of that wall. So we're talking 10 feet high by 16 feet wide, plus the two side windows. It will not be easy or cheap, but it will be done perfectly, and Polar Seal is who we're calling first. I would strongly encourage everyone to take a good hard look at this company if you're looking at window or sliding glass door replacement. I'm thoroughly pleased with the product, the price, the amazing construction and the professional installation.