I've used NHance twice. The first time was a few years ago when the interior finish of our multi-pane windows, damaged by a western exposure, was flaking off badly. NHance did a fine job of refinishing those narrow strips between the panes as well as the sills.
Recently, our wooden kitchen table and counters were suffering from too much food prepping, and had become gunky and damaged. Julio did a fine job of making both the table and countertops look great. However, while the table was fine, the finish on the countertops proved vulnerable to water damage. I had to call back and report the problem. They couldn't have been nicer about it. Julio said it was a product fail. Anyway, he refinished the countertops again and they are no exactly as I wanted them to be, and are holding up just fine to all the water that gets slopped around.
If it weren't for needing to call them back for the countertops, I would have given a 5 for total experience.