The best one I've found is the KO Propo PDS 2123. Digital, ball bearings, coreless, metal gears, 0.06 S @ 60° and 131.9 oz.
But this is for my needs, for some cars, it's important if the servo is smaller. And many people drives really good, with a servo, that is slower than the above. even though money dont matter, they might be better spend on something else.... Well, that's my way of thinking !
Some servos are programmable (Hitec and KO), but I dont need it, so why pay for it? If your radio is high speed, there might be some issue to take of too.
Schumacher Mi5 - Sanwa MT-4 / RX-462 / KO Propo PDS-2123 - Nosram 5600 X-treme Saddle Pack - LRP SPX Zero/X12 17,5 - Nosram Stealth Touch Evolution - MAAS SPS 9250