Here is my feedback.
When I had PBL V2 on my mom's car, the coating itself was doing so well that it did not need a topper. I purchased the coating booster and used it every few months just to use it. Other than that it was a simple wash and dry with the turbo car dryer. I did use ech2o the year it came out as a drying aid (QD mix). I never used a wax or sealant on PBL V2 coating.
With Ameriarmour on my Camaro, I used things such as quick detailers, spray waxes (that were sent for review), Cure, Reload and Ech20 most recently just to test out between the two toppers. Ameriarmour itself was an acrylic based coating and it lost it's pizazz and I was just looking to limp along until I re-polish and re-coat.
On my grand prix, I recently used Sonax CC36 ceramic coating and there is one area that is not being topped with anything. Other than using N914 as a drying aid. I am using Brilliant Shine Detailer every 2-3 months on the other areas to see how that affects the coatings performance. Sticking with the same family in products. I may try one area with polymer net shield at the 6 month mark per Sonax stating that it shares similar chemistry with the coating to act as a booster.
On my dad's car that currently has gloss coat, I ended up topping it with cure. I use ech20 weekly as a drying aid. The reason being that gloss coat was having performance issues. The car will be re-coated in the next few weeks.
On my mom's car I used Gyeon Q2 primer polish and Gyeon CanCoat. I recently topped that with cure a few weeks ago and use ech20 as a drying aid on a weekly/bi-weekly basis.
My brothers car also had Ameriarmour and that lost a lot of it's punch after the first year. Again underwhelmed with the paint coating in the long term. It too was topped with Cure until it was re-polished prior to selling it.
All cars are washed with CarPro Reset, Megs Hyper Wash, D114 or N914. I did use ONR with gloss coat for awhile but ended up going back to N914 and D114.
If i do top a coating I will use the recommended maintenance product from the same manufacturer. I do not use waxes or sealants on any coating.