My understanding is that for throttle servos at 1/8th scale you want a decent torque (100oz-ish) for good braking response but the most important aspect is speed. You want the transit time to be .15 or lower, the lower the better. The transit radius doesn't need to be huge unless you have a long travel on your linkage.
Edit* sorry forgot this part: I don't have any solid recommendations but I do like my JR9100S