Depends what you mean by a wavy blade. If you're talking about a blade with multiple curves, like a kris, that's already been covered. Recurve and reverse-S blades, on the other hand, are a different matter.
Recurve blades can be said to slash better (mainly due to the inner hawkbill like section), and can be good choppers.
Reverse-S blades (like the Spyderco Civilian) are (in terms of SD) excellent at slashing, but at the expense of not being able to thrust. For utility, a reverse-S blade like the one the Dodo or the Cricket has works fairly well.
Oh, and all PE wavy blades are annoying to sharpen compared to more conventional PE blades. It can be done though. If it's SE, then compared to a normal SE blade, it's about the same difficulty.