I have to give the Tiger my vote. The curvature of the shaft is meant specifically for g-spot stimulation, but I find that it's a wonderfully natural sort of bed (unlike some extreme angles g-spot toys tend to carry). The vibration is sort of in the base like Tuesday mentioned, but my experience with the Tiger is that the vibrations carry up evenly throughout the shaft, providing equal amounts of heady sensation for every insertable inch of the toy.
The Tiger also has to added benefit of being incredibly easy to thrust with. That natural curve I mentioned? It makes all the difference when getting that deep, throbbing vibration when pounding in harder and faster.