I've been using a pair of gauntlets since their release, can't go wrong with them. Here's my typical usage:
Phantom: I usually run one gauntlet, on my strong hand. I don't like to not have my hand on the trigger.
S6 with pocket hopper: both gauntlets, but more of an "oh ****" reserve of ammo.
Kp2: both gauntlets, as the gun is so long I want to be able to grab a tube with whatever hand is working the springfeed.
Yeah there are some issues. Mainly spilling paint, however if you pull the tube straight out rather than jerking it or pulling it at an angle, you won't spill any paint.
If you're running the tubes cappless, and the tube is not inserted ALL THE WAY into the loop, then the paint WILL break if the tube takes a direct hit. If it's secured, it's about a 50-50 chance the paint will break.
Runnin cappless is nice, just stick the tube in backwards when it's done, no need for a dump pouch and it keeps dirt from getting in the holder.
Breaking paint in the holder means its basically useless until you wash the thing.