My story is of the Cannondale Quick bikes but in reference to your post. I bought a large as I too wanted the immediate gratification of walking out with the bike. Rode it for a couple of days but I brought it back to my LBS and he graciously allowed me to swap it for a medium. Rode that for about 9 months and wanted a more road like bike but without the drops so I bought a Quick 3 but again they only had a large so I test rode it, bought it, and since then, it is the only bike I have put any real miles on but not without trying to get back on the medium. What all this is about is that you need to get some seat time on the two bikes and find the bike you feel can be tweaked, as both will, to be the perfect fit for your style of riding. I am solidly in the medium bike size no matter what bike brand but I ride a large. That is what fits and feels best for me and my geometry. Ride them both and ignore the labels. Get the bike that fits you. I am sure there are a hundred arguments against what I am telling you but with a change of the stem and moving the seat up and back the bike is a very comfortable fit. I have to admit that the standover clearance is not what I would like but that is something I will have to deal with while laying on the ground wishing I had rode the medium that day. That said, if I was still riding my steel Columbia of old there wouldn't be any standover so what I do have seems to be a gift.
Frank.