After many years, I lost my enthusiasm for polishing and coating, mainly because I don't have the expertise or patience to do it right. In the spring of 2019, I purchased a new SUV for my wife. I is driven about 17-18k miles per year, in all four seasons. I didn't know much about ceramic coating at the time, and I had polished it in the spring and topped it with Wolfgang Si02 paint sealant (a hybrid ceramic coating good for 6+ months). In the late summer the White SUV got covered in tar spray...a whole bunch of black spots all over. I knew that the only proper way to clean it required a new polish and sealant...something that would have been needed anyway before winter, but that was the tipping point on losing my enthusiasm for doing it myself. Thus began my journey searching ceramic coating and installers.
I chose the installer based on reputation and reliability, rather than the product. He uses CeramicPro, a proprietary product that can only be installed by a professional. The offerings were similar to yours with 2, 5, or lifetime guarantees, all of which require an annual refreshment (and reasonable fee). I chose the two-year deal and faithfully adhere to the annual refreshments. I have yet to have it recoated and I am extremely happy with the results. I'm fussy maintaining it, and although I don't like regular automated washes in the winter, it does show some surface scratching due to the nature of the tunnel wash...but it's very minimal and not visible on a white vehicle except on close inspection. The annual refreshment (which is really a light polish) makes that all disappear.
In the fall of 2020, I purchased a used 2017 Audi for myself. It's black and I purchased the 5-year plan, which has 1 coating of 9H, and topped with Lite. Since it's black, I never take it through a regular car wash. I only take it to a touchless wash and usually followed by a rinseless wash in my garage. I also follow up with the annual maintenance.
I'm very happy with both cars and recommend it highly. I'm not convinced that the longer guaranteed options are any better...although I don't regret the more expensive option. I recommend the 1 or 2 year deal to see how you like it.