Never had Smashburgers (there are none around here), but I'd probably avoid them because that method of cooking kills burgers deader than Raid.

Five Guys, on the other hand, has awesome burgers and great fries. (I love the peanut-oil frying.) Several diners around here also have great burgers. Shake Shack, which has a great reputation, is IMO only somewhat above average, and not worth waiting on line for at least 45 minutes.

I agree with filkerdave, though: I cook burgers better than any chain.