the all in ones have their pros and cons. the pros
generally are price, and packaging. you get a lot of performance out of a single package.
the downside is generally expandability, with a fixed lens, you're going to be limited on what you're able to do.
there's a reason why the most expensive parts of a "real" camera, is the lens. with an all-in-one, you are basically buying the lens, with a set of functions attached to it.
from that perspective, i don't think the all-in-one are a good deal, because you end up paying a few hundred bucks for a lens that's really more of a $100-150 quality. they work fine in "normal" conditions with good light and un-challenging backgrounds, but when you're dealing with low light, the all-in-ones just can't cut it.
BUT, they have their place. if you're looking to do limited things with the all-in-one, and its able to perform for you, then there's no reason to invest in bigger/more expensive equipment..