I used Convertabath several years ago. The workers were all very helpful and did a great job. However...after a while, the product started wearing off. Keep in mind that we had 3 full baths done, and only 2 of us live in the home (college kids are away). So it's not like the rooms were being heavily used.
Anyhow, Convertbath offered to touch up the areas, for a flat $65 labor charge.
So far so good. But the problem was (and this happened at least 2 times) that they never matched when they did touch up! Technicians said it was not possible. So I have a sink area that has tiles that are subtly yet visibly different from the other part of the vanity and a shower with the same problem. So the product is definitely NOT durable. In retrospect I would only use this as a short term solution.
The other thing to know (and this IS in the very fine print) is that you will no longer be able to use your soap trays or any suction-cups on any treated service.