The cases, lenses and frames of the regular and large models are almost exactly the same, and have no distinguishing markings. I bought my wife the regular and I have the large (I thought I'd need those since I have a fairly large head, but they are actually a touch too big), and we were using them in a handgun course at the same time. We got some of the lenses mixed around which was a problem-- the regular size lenses fit in the large frame (sort of) but the large lenses definitely won't go into the regular frames. I'd recommend to Revision that they mark the cases, lenses, and frames somehow with a "LG" or "REG" or some kind of readily distinguishable mark. Otherwise, the glasses are great. Very comfortable, lenses easy to change, and peace of mind knowing that you've got an optical fort knox in front of your eyes.
Pros: Lightweight, comfortable all day. Used polarized smoke lenses in Nevada all-day sun, and amber lens on cold overcast day. No eye fatigue at all
Cons: None (though see comments on a logistical issue)
This review was written in the old system and had content requirements that are different than reviews written today.