It's a neat little bag. Not QUITE a full-featured DG backpack. But if you only carry 12-14 and full-sized backpacks are too much bag for you, it's a sound option to consider at a respectably cheaper price point.
I offered my opinions here:
http://www.dgcoursereview.com/forums/showthread.php?t=81442&highlight=shift
They have confided in me that a larger backpack is in the works with the same style in mind, but assured me they have listened to the critiques from the Shift users and will be addressing those for the new releases. (Namely, the bag standing better on it's own, I hope) I couldn't get a date pinned down; just that it will be "some months" before it is made public.
Also, apparition, for around $50.00 less than a standard market offering, you may want to rein back the trigger finger and wait to see what the Contender looks like. I haven't seen it, but MJ seems to like it enough to call it his own, and he's a pretty cool guy by all accounts. Chris from PF has been nothing but professional and exceptional in our conversations. BillyR might get a little worked up from time to time, but don't let that deter you from Physical Flight. The bags are quality made, and a $155 backpack with a lifetime warranty is nothing to dismiss lightly.