Klasse AIO and SG were good prior to being reformulated. The newer AIO isn't as good as before. AIO is relatively easy to use, but put too much SG on and you'll cry removing it. A machine isn't necessary, as long as you make sure you use a very small amount.
Jeff's werkstatt is similar to the original AIO but IMO not as strong.
IMO, Zaino is good, but too expensive and too many steps.
Jetseal 109 is a very good sealant and easy to use, although the recommended 12 cure time can be cumbersome.
IMO, as long as your upkeep is good (wash often, wax or seal as needed), you don't have to use a product like AIO/Prime/etc unless you really need to clean the panel.
I currently use Blackfire wet diamond, but I may try the Menzerna next:
The BF is super easy to apply/remove, even easier than Chemical Guys Jetseal. Durability is about the same but the ease of use makes it my current fav.