Mrs Chimp loves the
Mantric range. The frequency is just perfect for her.
They're silicone, rechargeable, waterproof, quite firm, decent power, and they're nice and rumbly. They do have smaller batteries/shorter run-times than some of the more expensive ones, but that's not held us back so far.
Her favourite is the wand, but the rabbit is good (nice shape to it too), and the Realistic one is a decent g-spot toy.
My only caveat is that some of the bum fun toys may not last long enough between charges to get a decent session (especially the stroking one). Obviously it depends on how long you want it up there for, but it's something to consider.