There are lots of other variables to consider... For example the number of turns a day, and how complete those turns are to name some big ones...
I personally don't like the auto turners that don't actually turn the egg but simply rock it back and forth... I believe it's best to actually turn the egg fully if not every time at least some times...
Also frequency comes into play, I would argue that hand turning 10 or 20 times a day is likely better than an auto turner turning 3 or 5 times a day, and vice verse... Someone here posted a university study that concluded that the optimal number of turns per day is 96 times, something to ponder...
I'm in the very early stages of designing my own incubator from scratch, and I plan to have it turn the eggs in a more random fashion, sometimes turning them some portion of a degree, other times turning them the full 180º also this turn will be done at a more random speed... Also the number of times it turns per day will vary from day to day... Might be stupid overkill in the end but it gives me something to do and a chance to be creative...