A friend of mine just got the Jack rabbit and to be honest I was pretty disappointed with her because I've told her all about the materials and all that and I really thought she would have gone with a more, eh, sanitary choice?
Jelly is really gross.
If you look up the threads on toy materials, and what people's least favorite material for toys are, Jelly is almost always up there as one of the most hated toy materials. It smells horrible, disintegrates and melts when touched to certain materials and stuff, and they can "sweat" phthalates and leach those chemicals into your body.
And when you factor in that they'll probably break within the year and will need to be replaced with the fact that more expensive silicone and trp rabbit vibes often have replacement warrenties that cover one year or more, it costs about the same or less to go with the more expensive one.