I love my Ortlieb Backrollers. Got 'em on an REI sale a while back, only used a few times under duress, but superb.

I had the REI Commuter ~18 months ago (?). Returned it. The big honking studs/rivets for the attachment points stick too far into the cargo area. Though they're covered with a little plastic, they were punching big, permanent indents into things like binders, boxes, etc. that I was carrying. I don't know that they would damage a laptop, but they damaged enough semi-rigid things that I was done. Otherwise seemed a nice little bag.