Well, I live within walking distance of
B&H -- walk past it every week or so and do like shopping there. But there are a few good reasons not to spend too much time there, even if you live close by:
1. It can be a madhouse, particularly on Sundays. I can't bring my girlfriend there, because she hates crowds in tight spaces (why she lives in Manhattan I'll never know) -- and it's often very, very crowded. If you have something in particular you want, that's ok - but for general browsing it can be a pain. (The lens section in particular can be virtually impossible to get into sometimes...it is as crowded as a nightclub dance floor at times; you can barely move.) Weekdays aren't so bad - but I'm at work.
2. Tax. Beach Camera offers comparable prices, and...well, technically you still have to pay state income tax at the end of the year, but let's just say that it's not paid automatically.
3. It's huge as camera stores go, but in the grand scheme of things there is only so much that you can put on display in a Manhattan store. After a few times, you've seen much of it.
4. You don't want to be "that guy." You know, that guy that hangs out at the guitar store, "testing" the guitars and never buying one. Or the guy who is constantly shopping for new camera bags, or just dropping by to see if the new lens that he's not actually going to buy is back in stock, so that he can putz around with it for 20 minutes without buying it.
Nonetheless, it's a great store, and definitely a good place to come if you're in town.