The first important thing about car polishes is to know the manufacturers/retailers/importers have a large budgets to spend on advertising (look at any car magazine). This means claims about product X being superior to product Y are often a bit marginal, and they are nearly all too expensive. They are largely the same. The thing is that people always want to believe that spending a fortune is a good idea, and all the stuff about rare waxes taken from the ears of Komodo lizards or whatever is all tosh - like women's cosmetics products usually are. Same idea in the end!
I've been lucky to have tried a few of the expensive brands used on some of my previous cars (although I didn't have to pay for the polish!), and honestly there's not a huge difference in shine or longevity compared with many cheaper products. The air quality and weather in most of the UK is so bad that the polish is stripped off pretty quickly, so IMHO, best to buy cheap/easy to apply, and use regularly if you care about it. I suspect the easier it is to apply, the quicker it comes off. If you want long-lasting shine you need harder waxes and electric buffing kit....
When my truck got 2 years old I washed and polished it, rather than letting the weather do it for me. I used Halford's Mer Ultimate Shine. It was OK but madly over-priced considering what is in it. Lasted maybe 2 weeks. Certainly easy to get on/take off, but I have a white Nav - any black vehicle is much harder to keep clean and polish up, so I avoid them these days! Also, white is so much better for hot places like Spain/Portugal where I spend a lot of the year.
In the end we have trucks, not concourse-condition exotic cars!