Will go well on W or E coast but tougher inland, needs to be the right city. No good where city has no-smoking no-vaping indoor bans (or might bring them in), obviously. Virginia should be OK as the State AG has already said vapor is not smoke and can't be banned indoors

(but check for your city).
FDA might kill the legal end of the aftermarket/upgrade business (the stuff we are interested in & you would be selling), so it's a high-risk bet right now. B&M was a great bet 2 years ago but the FDA decision may be getting closer - get in if you can find a place with ultra-low overheads and you don't need to take out a loan in order to get started. Keep in mind you may only have 1 year before things get a lot tougher. There will always be ways & means, for example if some stuff is banned then you can have demo units & a web address to get delivery from, and so on.
A place with excellent parking or high footfall is good, somewhere with no easy parking or no passing trade is no use. But the overheads are the main issue, and if you can get out in a year with no penalty.