Bird poo can be a big problem. On our Golf, which is red, most poo etches into the lacquer within a couple of hours and leaves a lunar surface. It can be eliminated but only with vigorous cutting back which isn't great. I always carry my poo remover kit, and act immediately.
Meguiars seems to be the best performance/cost balance.
I do use Swissvax occasionally and the polish is good but I would defy you to tell the difference from Meguiars.
I tried Bilt Hamber Craig. It was promoted a lot by Practical Classics, and a big advertiser. I still have some on the shelf, but I didn't find it as good as Meguiars.
On my previous Golf I used a different polish on every panel as a test. The water droplets varied slightly, but in terms of shine and longevity, there was no visible difference.
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4
