I called Derek in to provide an estimate after I had a flood that ruined my laminate flooring. I also got estimates and chatted with a number of other concrete polishing providers, and it was EVIDENT to me that Derek knew infinitely more than any of the others and his estimate for the work (though not guaranteed) did not change.
He didn't send a crew of random sub-contractors, but rather did the work himself with another team member. He didn't use epoxy-type coatings that wear off or otherwise have to be re-done every few years as they wear or peel off.
They were VERY careful (as much as one could be given my narrow hallways) and tried their best to keep their equipment from damaging the paint on my walls. There were only a couple of minor scratches, and the rest could be wiped off.
My floors are PERFECT. GORGEOUS. They were ground so smoothly and evenly that I can see the reflection of things outside my window in them.
Thing one to note: you are responsible for removing the bags of dust, which can be quite heavy.
Thing two to note: concrete polishing is dusty. Imagine the dustiest environment you have ever been in, then multiply it by a million. And the dust is so fine that it is VERY DIFFICULT to remove. In fact, it proved to be impossible to remove without having a shop vac with floor attachment. (Swiffers did nothing). Derek and his crew cleaned the floors very well before leaving, but I had to do a LOT of prep work to ensure that the dust didn't permeate my furniture/kitchen cabinets, etc.
Overall, great job, really pleasant to deal with, accurate quote and fantastic work.