As a new user (5th May) I can say that so far I have had no issues at all.
BP and Shell cards come with the car.
You will have to pay either the full or part amount depending on timescale.
You may have to wait for the car you want but a new order works fine.
I have a Zoe GT and will be moving to a Kona in June.
only cost is the change fee but I guess I saved that with the referral code I used.
I used a referral code for discount on the first month.
Feel free to use mine its helps us out to share.
referral code is: 5a2c7
The team are great to deal with and answered all my questions on the telephone or webchat.
No regrets so far here.