We installed these a short while ago, and so far am very impressed. The windows look amazing, and almost immediately we noticed a reduction of street noise. The house also feels somehow warmer and better sealed. We have more light coming in now because of the way the blinds are stored away, and the solar/blackout screens have been great whenever we need privacy. You should definitely consider these if you are looking to make a change to your windows!
Re: the sales process, the company representative (in my case, Vysan) came to our house, was able to talk about the options and show how they compare to what we have. We also went to their showroom to see things in action.
After we made the purchase decision, everything went smoothly: the company sent us a sample to show our chosen colours, booked the visit, and they showed up right on time. We were doing a lot of windows and also our patio door, and things moved along quickly: 1 day to install, and the 2nd day to do trim and other detailing. Afterwards, they even came back to make sure that we were happy and do any fine-tuning and other adjustments as needed.