Anyone have a Speedlite?

brightning

I got a Speedlite 270EX for Christmas. I used it a lot that day and sporadically since.

I replaced the batteries this morning because the flash hasn't been turning on when I turn it on - it takes a minute or more after the camera is operating before the flash starts working (no light at all, not even a flashing red to say that it's warming up). Changing the batteries seemed to solve the problem, but it seems odd to me that no lights turned on the flash when it was turned on, and then it worked fine after it finally started.

So I guess I have two questions. Should I use regular AA batteries or the lythium batteries - maybe that's what's causing the batteries to run out so quickly. Or do you think there is a problem with the flash and I need to exchange it?