What's 'best' depends on what you're looking for? Small fields (iPoker/888) or the best software (Stars/FullTilt). I find the Ayer pools on different networks vary in style and ability - it's not as easy to win (in the long-run) as it was even a couple of years ago, and it's a lot harder to find value now. I have to recommend trying Dusk Till Dawn's site for their excellent selection of live qualifiers.
Do you use tracking software? If not, and you have no interest in starting to, perhaps focus on the sites that ban them so you are not at a disadvantage in that respect. I can't remember which ones ban them off the top of my head, if anyone can help?
Sky ban tracking software.