As far as having to get some 121 background in an RJ...with all due respect, GMAFB. Flying an airliner from point A to B, absolutely, positively in no way compares to military flying. And no, I'm not saying there aren't quality civilian guys...there are plenty and I've flown with a bunch of awesome guys, both flying wise and personality wise as well. But please...military pilots transitioning to airline flying, takes oh - maybe 6-9 minutes after you figure out the crew concept.
All debate aside, the toughest thing I found coming from the single seat world to flying a fatty at .78 M was how to integrate into the crew concept arena (i.e. when to read the QRH, how much interaction was required, how and when to talk on ramp, etc). Once that part was understood...which takes about a day or two, the rest ain't tough.