There is no 'Best', unfortunately, lots of people have different opinions about what works best for them: Lake Country,
Meguiars, Propel, Edge,
Sonus... those probably cover the majority of opinions you'll read on here. Personally I've used Propel (P1 & P2), Sonus SFX & LC (flat and curved). My favorites (based on ease of use & cost) are probably the Propel pads, and I really like the velcro that goes all the way to the edge on the P2 propel pads.
However, almost everyone who responds will probably have a different favorite for a different reason. My recommendation, don't buy a whole bunch of 1 brand of pad without trying one out first. Yes, you will pay a little more in shipping to try a couple pads out, but in the long wrong, you'll spend less than if you buy a bunch of pads you don't like.
edited: fixed typo