I passed by The Forbidden Planet in NY to get some issues and asked the workers there about Justice League and they gave me mixed reviews to see it for a lot less later on iTunes or cable TV.
Huge stores like FB, Midtown, JHU have so many issues, trades, t shirts, statue figures, and so much more comic and scifi paraphernalia I can browse there for hours. I thought it must be like heaven to work there but then I thought that after a while all that stuff gets to you and the bottom line is it still a business. I you do leave it would be hard to be taken seriously as experience when applying somewhere else.
So in conclusion I have to say that a comic store is nice but actually working there day in and day out has its ups and downs.