Both are a freakin' ways from me. Even when I lived not too far from DU, both were still freakin' out in the boonies.
I've been to both. The one out in Aurora, I think, is a little more crowded, layout wise. They seem to both have the same scale model selection of aircraft, but the Aurora one having more "other" ships GVs etc, and more radio controlled stuff. To be fair it is a larger store. The other store is the one in a shopping mall type of area, and Aurora is the one way the heck out there off some big highway right?