I just completed applying a ceramic coating to the dark blue hull on our '21 R27-OB, so I can tell you about my experience. First, a caveat; I'm a die-hard DIY guy and I'm really good at man-math, the concept that if a professional quoted a job for $500, I could buy $400 worth of tools to complete the same job and the tools would, in effect, be "free". And, I'd save a few bucks to boot! This may or may not apply to you, depending on how you value your time. My wife would tell you I value mine below market rate, based on how long it takes me to acquire supplies, do research, and get the work done.
Anyway, I used System X Xtreme ceramic coating. I chose them because they appeared to have a "professional-grade" product that they would sell to me, a consumer. My research indicated that most high-end ceramic marketers would only sell to commercial installers who were certified in their product. This is for good reason, because my experience applying ceramic is that it's not all science - there is a bit of art and voodoo involved, as well. A lot of companies are putting "ceramic" on their product labels but they are not true ceramic coatings, so choose your product carefully.
My hull was in good shape, so I prepped it with Marine 31 Captain's One-Step compound/polish, wiped it down with alcohol, and then went over it again with Starke Triple P polish. The application of the ceramic was pretty straight forward - wipe it on, level it with a microfiber cloth, and wipe off the residue when it begins to flash/evaporate. The first coat went on very well. As I was half way through the second coat, the humidity began to go up and the application process significantly changed. The time from application to flash increased quite a bit and it became harder to time when to remove the product. That's the "art and voodoo" part. I can see why companies limit who they sell to because it would be easy to screw this up and then try to blame the product.
I expected the process to be a lot of hard and tedious work. I wasn't disappointed. There's a reason it costs several boating units to have someone do it. But for me, the results look great and were worth the effort. The hull has a great shine, looks cleaner while cruising (less salt-spotting) and is easier to keep clean. This is even more noticeable on the outboards. It's also looking like there is less fender rash than before the coating.
I'll begin doing my topsides tomorrow - much less real estate but a lot more detail work. I'll be happy if my results hold up for two years before I need to do any significant work. I will be applying System X's maintenance spray regularly to maintain the shine.
Hope that helps!