I don't think it's all hype, but there certainly is a lot of hype there, and most of the benefits will only come if you have a B-vitamin deficiency. Lots of people do, though, so there may be some benefit for quite a lot of people.

But on top of that, B-vitamin complex pills benefit from a lot of side-effects of high intake, including e.g. Niacin flushes and tingling effects, which I thin probably boost the perceived effect well beyond any actual effect.