The workers who came to do the job did work quickly and efficiently. Unfortunately there were some problems.
The workers did not speak English, making it was difficult to communicate. The only Russian I know is "Hello" and "How are you?".
Cleanup wasn't the greatest. There were still bits of glass in our lawns and window wells after the workers left.
It was explicitly stated in our verbal agreement and on the contract that all of the windows were to be frosted. Only one windowset was frosted. Although they offered to come in at a later date to put in the frosted panes, they failed to explain how that would be done without release the supposed "argon gas" between the panes that apparently helps with insulation. We didn't want them back, so we declined.
They did reimburse the extra cost for the frosted glass but only after an unnecessary negotiation process over the phone. (They initially quoted $25 extra per window for frosting but when negotiating the partial refund they said it was $20 per window - um, excuse me?)
Sadly, I cannot recommend Mr. Windows & Doors. Too many unnecessary problems.