We bought our house as a fixer-upper and had to reno everything from top to bottom, starting with the roof. I knew of Zim Group through my work - we do business with a lot of different contractors in every industry and Mykola always struck me as someone who believed in his product and cared how it was installed.
More than anything, I think that was what made me choose Zim Group - in whatever work you have done there are so many ways that contractors try to skip corners, both out of greed and lazyness, and that just doesn't happen with Zim Group. They even imported the screws from Europe because the North American ones tend to bleed rust.
The product itself looks good, but the quality of the metal is the big difference, with superior metal and coating. If you want to know everything there is to know about metal grades, Mykola will happily fill you in and I know it's for real because he went on about it long before I had a house to put a roof on. After you finish that hour-long conversation, ask him about the importance of attic ventilation and how asphalt shingles contribute to asthma. I'm pretty sure you'll have a degree in it after he's done.
There are so many contractors that are little more than salesmen - they want to sell you, then toss of a shoddy job and call it a day. Zim Group actually thinks about the purpose of what they're doing and does it right. I had them install a skylight and some plumbing vents while they were at it and I looked up some online videos on different methods ("trust but verify" and all that). The installers used the most quality and time consuming method with some on-site metal-working I didn't even see online.
I'll wrap it up here, but bottom line: it's an excellent roof made better by excellent installers.
P.S. The picture are a little ify because the house facade isn't done yet, but the roof part is top notch.