I bought a very old HQ16 that did not have the regulator. Not every stitch is exactly the same size but I do not make show quilts. Once the quilt is washed and dried it makes no difference at all.
Friends tell me after a while they "outrun" the regulator. I am not quite sure what that means but I quilt fairly quickly on my HQ. They ended up turning it off.
That being said--I do not do pantos. I just quilt free from the front of the machine. I think it is very helpful with those.