Meguiars for me, been using it for years with excellent results. About twice a year I go over the finish with detail spray and a clay bar to remove all the air borne junk that settles on the surface.
I had a Meguiars rep at a car show several years ago ask me if I had ever used a claybar, when I said no he left and came back with detail spray, microfiber cloth and a piece of claybar about the size of a 50 cent piece. He then said you have a great finish on your car, smooth, great shine, but watch this...he proceeded to do one half of the trunk then he had me feel the half not done...then the half he'd just done, what a difference, the finish even appeared deeper and shineier and was smoother to the touch than just the waxed portion. He showed me how to use it and I was sold so to speak.