The typo on the subtext looks familiar. I swear I've seen that font used before, and on a logo too. Not that it matters, but it's a pretty identifiable font (although since I can't remember where I saw it, not identifiable enough I guess). The whole glossy shine of it all isn't all that appealing to me, but I guess it really depends on what the actual business is supposed to be. What stands out most is that white gradient that sits on top of the text; that is probably going to be a breaking point when you try to use it on different mediums. The only thing I can see that might be a downfall to this particular logo is the proportions used in the actual logo and compared to the text below. The logo actually seems stretched vertically, and it looks a little awkward.

As far as your question about sans-serif vs serif, there's a chart floating around somewhere that shows typographically sound matches between the two styles of font face. If I come across the link, I'll share it with you.