Can u specify your understanding of best. There are some high end servo brands like futaba, ko, hitec, savox, radiopost, protek, expert and so on. Each one of them has its own advantages over other servo brands generally. But i can say i bought xpert si-4431 servo recently. And u can bought it from amain with discount coupon. It costs 65 usd. Its an brushless servo and its specs are 0.08sec/60degrees and 17.5 kg.cm which are good specs for both 4wd sct and 1:8 buggy. And i think its one of the best cheapest high end servo