I'm talking about the legit wireless unit they had at NAB this year, not the iPhone one. A big FF knob with an antenna controlling a unit across the room with no noticeable latency. RedRock has the best bang:buck ratio out there, I'll stand by it. Granted, I'm not a full time 1AC, most of my time on set is spent elsewhere. If I was turning a focus knob 12 hours a day I'm sure the differences would mean a lot more.
I think they're two different versions of the same thing - one with an iPhone, one without.
Yeah, I had a 5 week shoot earlier in the year as a 1stAC using RRM gear and it was not the greatest to work with. I ended up having to re-tighten the follow focus gear daily as it would get worse and worse through the day and end up with half a turn to a full turn of play - I ended up marking up the lenses themselves and pulling off those. We had the matte box fall apart, which I had to fix as quick as I could, the rods were too long for the lens, and the tightening knobs were in awkward spots which meant we couldn't place the units where they needed to go - in turn causing internal flares on outdoor stuff, the FF itself is only designed to be used on one side which made pulling from the other side difficult - not only was it focussing in reverse (ie forward to throw back, back to throw forward) but the unit had to be placed so far forward to work with the lens gearing that we couldn't use a matte box...
The shoulder pad seemed to be fine though haha

This is just my experience, and it really illustrated to me the reason why the more expensive units are the units of choice, and in fact why they are more expensive.
But, some swear by the RRM stuff, so if you've had good experience with them, then by all means stick with them.
Side note, we bought an RC copter beefy enough to fly a GoPro around for about 20 minutes per charge at NAB. $600ish with tilt controls and a wireless video transmitter. Been a lot of fun so far, can't wait to use it in a production. Same company makes a DSLR sized one but only has about a 12 hour flight time per battery. It's not quite as nice, but a bird of the price as an octocopter.
Yeah, I reckon GoPro is the way to go on a copter - the small sensor and wide lens means you're gonna have very little focus issues.