Pros: I hear Liquid Glass is good. Nu Finish is the easiest finish I've ever used.
Cons: Expensive, I don't see Liquid Glass as being any better than other polish.
I've tried quite a few car polishes and I don't see enough difference to justify buying the very expensive ones like Liquid Glass. Meguiar's products are fine. The best I've used though is Nu Finish. It goes on easy and comes off easier than anything else I've ever seen and is the only product I've seen that can be applied to a hot car in full sun. It does last longer than plain waxes too. If I want to protect the finish more I put Meguiar's carnauba wax over the Nu Finish. I always recommend Nu Finish to anyone. I also always use it on my wheels to help prevent brake dust from sticking.