Good: The windows are beautiful and seem to be doing well their job of insulation. The company shows its interest in customer service by responding promptly, personally, and courteously to questions and issues.. Bad: The windows are REALLY expensive, but I'm not having buyer's remorse. At that price, I expected absolute perfection on the day of installation. I was disappointed. There were nicks and a little bit of mess that should have been taken care of. However, a guy was sent out promptly to fix things, and after him a crew to thoroughly fix the major outstanding flaw. Windows are perfect now. Salesmen somewhat misrepresented the manufacturer's warranty and the material of the windows.. Improvements: Salesmen should explain the manufacturer's warranty accurately and distinguish it from the unwritten warranty/policy of Penguin. They should admit to the windows being vinyl, distinguishing them if appropriate from other vinyl windows. Installers seemed a little pushed for time. Our job was a tad more than 1 day's work, which may explain the imperfections left. Incentives should be given for achieving perfection even if it means another hour on a long day or coming back another day.. Other: The windows are beautiful and perform as represented so far. Even though the manufacturer's warranty is not as generous as represented, Penguin's policy of customer satisfaction seems sincerely and effectively implemented and supplements the manufacturer's warranty effectively. I hope Penguin management continues this policy throughout the years. I am so far content with what I've purchased (2 large slider windows, 1 slider door, 1 casement window)--I think the money was well spent..