I bought the MavMount and it just arrived a couple days ago.
After spending some time with it, I have to say, this thing is the REAL DEAL. It is extremely well made - a quality addition to your Mavic Pro. I looked closely at the other mounts, but the plastic is not the way to go. What I REALLY like about this is the adjustable nature of it. And no, it does NOT block the antennas. In fact, I'm also using one of the antenna boosters with the MavMount and no issues.
Because of the adjustable feature of this mount, you can get it adjusted to where the "balance" is perfect in your hands. It feels awesome. Yes, it blocks the screen but who cares? Everything that is on the controller screen is on the tablet screen and it's BIGGER so you can actually see it. Have an issue with your tablet app and need to see the controller screen in a hurry? Just twist the knob on the mount and swing the screen down toward you in an INSTANT. Done.
While it does not have a hole for a lanyard, that's no big deal either. I simply took mine, wrapped it around the shaft and hooked it to itself. Done. Works perfect.
If you want a mount for your tablet, you can't go wrong with this unit. It's well made and will adjust to where it's "just right" for everyone and it stays put. After having this thing, I'd be embarrassed to use one of those 3d plastic things.
I've bought tons of stuff for my other drones (including my Turbo Ace Matrix) and I have to say this is one of the nicest, most well made pieces I've acquired. I don't usually "sing the praises" of something, but this one deserves it. My only concern was the weight, but now that it's in my hands, I worried for naught. It's fairly light and it nicely integrates with the controller so that the whole package, weight wise, feels just right.