It is a lot like women, red heads or blonds?
I have use Meguires for years and find nothing better. Click here
The Power cleaner compound is by far the best in my opinion (I know, stupid name). click here
Mequiars is like Evercoat to me, I have always been happy with them and if they made TV's I'd buy one.
We use the 3M system here at work day in and day out (I am not in detail so I am not using it) so it is a fine product as well, you can't go wrong either way.
Ray, have you ever tried the Power cleaning compound? You can not believe how little you use, no compound shower using this stuff. And the "Unigrit" wet paper Mequiars distributes, holy crap that stuff blows away everything I have ever used (I am old school no DA for me).