I've got an Airtronics 94145Z servo NIP. for $50 shipped.
I ran these in a Legend and a 1/12 pan car on 1S Lipo WITHOUT a booster (Old Novak GTB ESCs would run fine on 1S).
It is listed as 0.09 sec transit time on 4.8V so I found it plenty fast, and never glitched on unboosted 1S LiPo.