i bought the beadlock loose tenoning jig from rockler quite a while ago and overall was not pleased with it. I realize it is different from the Jessum, which I wish I'd bought, but after my experiences, I am not a fan of drilling out mortises (except for on a drill press). I basically had 2 major problems with it:
1) my drill would poop out quickly b/c it takes quite a lot of power to maintain the torque to hog out the waste. Even with a quick re-charge (18v hitachi) it was a pain for more than a few of these at a time, which is the whole point -saving time not having to cut/fit the tenons! also, the drill bit included w/ the rockler system, dulled quickly adding to my frustration.
2) alignment was a major headache. the beadlock system is absolutely unforgiving for minor alignment issues due to the beadlock style loose tenons. Here a more traditional loose tenon may prove better like the jessum. That said, w/o a longer fence to reference the workpiece, it's not that hard to be slightly out of square for the two tenons at which point lots of paring by hand is needed.
nowadays, i use a router jig for mortises and cut tenons on the ts.
just my $.02.
Sam