ive used zymol and P21S.
Both are great. Zymol is more expensive but gives your car that showroom shine.
P21S is good for a quick shine that looks great, but it wont last as long as the Zymol.
I would recommend both to everyone.
Also i noticed that someone mentioned they use a automatic buffer. From what I have been told is that machine buffers are bad for your car because you can damage the clear coat and also you can buff out off the wax you just put on. thats what I have heard. I personally am more a fan of hand buffing.