Be aware that speed is not the only information you want to know.
Brands can mention fast speeds but you have to look at the angle too!

A servo with a speed of 0.1sec over 60 degrees is like 0.07sec over 40 degrees and there are brands using 40 or 45 degrees for their speed.

But if you have a fast framerate radio (like Futaba HRS or Spektrum 5ms framerate) you will notice the faster the better.