My personal preference is TriBot.
However, I am by no means an expert.
Also, I'd like to believe that ban rates are pretty equal amongst all clients for the most part. Its the scripts that will make or break you
Tribot/robotzindisguise is the best for paid botting in my experince.
Free bots hmm not really sure but I'd say TopBot or osbot.
Also Powerbot is good but I haven't used their bot in over 5 months if I'm honest.