Brian,

That's the refresh rate, or how often the servo refreshes the last given command. This is where the bit about digital servos having better holding power versus analog comes from. And FYI, analog servos were typically 50Hz and thus, far easier to push off position. And yes, the rate is higher (faster, or refreshes more often) on newer generation servos than old ones, which may be 100Hz or 125Hz. As for the high pitched whine that drives folks crazy, this is more about saving money on tuning the PID circuit (and money dominates consumer products). However, it's a subject far too deep into the weeds for a casual conversation with consumers, no offense. That said, modelers (if you ask around) are generally pleased with how quiet our servos are. Moreover, our servos, (all of them) are 4096 but we don't make a big deal about it. Added to which, all of our servos are soft start, also (meaning if the weight of a control surface makes it move toward the ground, then when you apply power they come to neutral slowly instead of banging into position quickly, which can be hard on structures and linkages). Again, we don't make a big deal about a basic feature - maybe we should. Finally, our servos are not programmable on purpose. I part, it's because we strive to minimize what's referred to in the business as the threat vector. Basically, a minority of our clientele are comprised of modelers to whom threat vectors (or ways of being attacked) are of little consequence. However, we give a lot of consideration for issue which our principal clients fret about, and you'd better believe they have a focus on avoid systems being compromised like when servos have firmware which can be flashed. Lots of bad juju involved in this so it's a big deal and why we leave servo programming as a function of the transmitter, instead. The other reason is programming leaves servos performing more slowly due to the code-overhead involved and thus, as a general rule, when comparing apples to apples, our servos are significantly better performing in terms of speed than servos which can be programmed. So as Mark Twain once wrote, you pays your money and you takes your choice!

By the way, since you mentioned it, the Hitec HS-5585MH crosses over against our DS255BLHV, and while theirs is about 10 bucks cheaper, it's also more cheaply made in our opinion. Put another way, ProModeler gives you more for your money because you get . . .

. . . so you're getting a motor that lasts 5X longer, more rigid aluminum case (one that sheds heat far better when the servo is working hard), significantly more durable gear train, plus hugely better performance (nearly 3X faster). And no, I'm not saying theirs is bad, saying ours is better.

They are quiet, dead center centering every time. A little more expensive, but why would I hang my year of work and research on the cheapest servo, that really doesn't make sense. A little thing, but the mounting screws are Hex Head which makes life so much easier.  Think about that the next time you groping around trying to find the **** thing. I'm not an electronic whiz kid but John Beech is and when you call his company it is likely he will answer the phone and if he has the time will gladly give you a tutorial on what ever you want to know.  Just sayin'.