Removing a device midline, while weighted, with ANY device is a very straightforward move, but that's not what Boston is seeking.
(I'll explain how if anyone's really mystified, but you would do this if you were on your way down and, oops, left the pole pruners hanging up there!)
To have a device that can pop off with the flick of a lever I just don't see as a good thing in arboriculture. We cruise through brush, might have a snag in the wrist portion of our climbing gloves, whatever. Instant release is just a hair faster than release of something else, once on the ground. Seriously, how long does it take to release a 6-bar rack? Even the scarab, lengthen the bight, flip the crossbar out, you are released. Fig 8; release biner, pull the 8, you're out. Where things get slow is whern you throw a friction hitch into the mix and then have a couple independent things to release, but even that is fairly quick, just not instant.
Next, with the De-Jump you route your rope through almost identical to a fig 8. You're almost certain to be twisting the rope. If that means nothing to you, rappel 50 feet with a wad of rope still on the ground. You may not make it to the ground because of the coiled twistedness that concentrates just before you reach the ground. This is asking for a hockle.
Lastly, I would dissuade anyone form using a device that is aluminum, if it takes all the friction. Aluminum wears and deposits oxide on the rope. A device is rated when new, but the device weakens when critical rub surfaces wear, then the rating is no longer 'as rated'. You keep using it, it's your life.
Yea, yea, aluminum is light, but even the stainless Scarab is only 100 grams. I wouldn't consider that even an issue climbing a tree, let alone a crane lifting you and dropping you into place.
