5 stars: Loooove me some Zipcar!! So glad I found this and such a life saver. I have never experienced any downside or frustrating thing with Zipcar or their app. Had to call them once for an expired promo code and they added it back to my account no problem. The only thing I would say I dislike is the young driver fee but that I can understand.
4 stars: Cars always available, nice selection to choose from and customer service always available to help. Easy to search for cars, either using local.map or click button for a list, pretty straight forward. Only one negative, sat nav doesn't work in the cars I've used, unsure why option is disabled.
4 stars: Great go-to for all things car. Esp in London. Ridiculously convenient (for me). Reliable. Easy to set up and access. Free fuel. No Confestion Charge. Happy (and useful) customer service reps. Fair pricing too, though would love to see a wider variety of multi-day deals and a longer free mileage allowance (cross-London travel can gobble up the miles, never mind leaving town).
3 stars: Generally great experience, but there is some problem with the signing in to the app, although I've selected to keep me logged in. I had to rent a car trough the app very urgently and that happened. Also I tried to call the customer service on couple ocasion, there was no one to answer my questions. That is why I take 2 stars.
4 stars: The app is awesome. My only complaint is that when I switch apps it forgets the search I had open...