I live near several of each, and they all have very different fish situations. And that variance changes individually month-over-month due to employee turn-over rate. The Smart nearest me is unique in that it, on a regular basis, holds several breed of fish I've not found at any other Smart or Co. Like serbai corys, or blue rams.
The nearest Co has an exceptionally good plant selection, with a large, leveled waterfall hex tank holding plants of various sizes. I'm also a huuuge fan of the clearance shelf. 50-75% off. Huge containers of fish food for $2? Yes, please!
My closest LFS had a recent ownership change, and it was in terrible disarray and disrepair the last time I visited. Most of their tanks were empty, and several of the fish from their large bass tank were "missing". The (current) problem I have with most other LFS is that they tend to focus and have knowledge mostly on salt water fish and corals. Fortunately, the owner of one of the LFS has a virtually infinite knowledge of all types of aquariums and it's always a disappointment when I go to visit and he's not working. That particular store has nearly 100 tanks, including tanks holding nautilus, discus, large predatory fish, an amazing full reef tank, and two incredibly well planted tanks. Stuff you will never, ever find at Smart or Co.
As far as ordering supplies, it's whoever is cheapest. But if I were to order fish again, for say, another tank, I couldn't suggest
www.aquariumfish.net more highly. I would give them an 11 out of 10. The cost of shipping is definitely worth it. Their specimens were all the best I've purchased.