Ah the gadgets.
We've rented 3 times, once for the tdf in Yorkshire, twice in the counterweight continent. Each time led to feelings of "wouldn't it be nice" which passed fairly quickly.
Chief among my reasons were the knowledge (from one dodgy van on Australia) that I would not be happy with a £10 one,, in London I have nowhere to keep it, plus the size of the damn thing. Bike is fine for errands and solo bike, but Mrs Ham can't manage rides any more.
The idea of the freedom offered is very appealing, though. Oh, and stuff like BBQ, packaway tech and other cave stuff.