They both conceal about the same and the extra 3/4" in the full size really makes no discernible difference in accuracy, but what really counts is how they feel in your hands...balance and pointability, big points in a defensive handgun. All that said, both are heavier than an anchor for all day carry. My son #2 built me a beautiful shoulder rig with a dual mag carrier on the other side, that seems to mitigate the weight. Belt holsters, OWB types work OK but I'd not like to tote one all day long, and I've never wanted to redo my wardrobe to accommodate an IWB.
I have both of the Rugers, like them a lot but do not carry them on a regular basis. In quality, both are well worth the money...locally here in Louisville, KY, you can find them for +-$650 -$700. In the examples that I have, they've been just about 100% reliable...failing only when I seated some LSWC's too long. Again, in the examples I have, their parts are interchangeable with Colt Series 70 guns. I think of them as almost perfect with regards to features, adding only that I'd like to have tritium night sights on them and a checkered front strap...of course at the same price.
Some here, call them overpriced entry level guns, but my experience has been outstanding with accuracy that's as good as my Colts with Wilson barrels and bushings.
Were it me making the choice, I'd go with the CMD's shorter barrel, but only because the Commander balances better in my hands and consequently, I shoot it better. Come to think of it, with all Ruger's experience with aluminum alloy gun making, I'd hope they'd put out a true Lt. Weight Commander of their own. I'll be first in line if they do!
Best regards, Rod