I've been using a QB coupler for 4 years now...
http://www.airforums.com/forums/f464...day-46178.html
I'm very pleased overall with the QB...just a couple of issues you need to be aware of:
1. the 'tabs' on the front of the JAWS extend forward enough to interfere with some hitches (not WD type hitches) that have a 'downward bend' to them - the distance between the ball & the 'bend' may not have enough clearance for the 'tabs' on the jaws...not a big issue, only comes into play if you have a temp hitch bar with big 'drop' that you use for backing, etc... see my post# 12 here:
http://www.airforums.com/forums/f464...ice-93014.html
2. you can't hook up to a ball if your TV backs up at an angle from the side, like 90 degrees, etc...you need to back into the QB from the front, with maybe a 10-15 degree limit...HOWEVER, if you backed into a spot and unhooked, you will be able to re-hook from any place you unhooked from...
The QB is extremely strong, and with the SS jaws, I don't use any grease on ball - just a slight spray of WD40 type stuff once in a while...
It would be virtually impossible for a trailer to become unhooked from a QB by virtue of it's design of completely enclosing the ball...
For added security, I insert a 'sawed off' ball into the jaws and lock the SS pin into place when parked - the 'sawed off' ball fills the 'hole' underneath so a thief can't insert anything there to tow the AS away!
Hitching & unhitching is easy once you get past the learning curve...the trailer coupler height needs to be rather close to the to ball height - I keep a 3ft wood dowel handy-back up the TV close to the trailer-measure the ball top height with the dowel & thumb-move to the trailer with the dowel to adjust coupler height to match...
Unhitching is easy, but best if you lift the trailer coupler just enough to take to 'weight' off the hitch ball, as you need to raise the QB locking band before unhooking... there is a 'tab' on the front of the QB locking band, and after removing the locking pin, I place it under the tab, holding with a hand on each end to 'pry/lift' the locking band - if it resists, you haven't taken enough of the load (or too much) off the hitch ball...
I'd do it again if I had too - the QB is a quality product if installed properly, providing a secure connection between the TV & trailer, and should last the life of the trailer...