Was not be good

Waited in line for 40 minutes, very slow. The most bizarre thing is, it was my first time in the UK, and they claimed I was on their blacklist and refused to rent me a car. I ended up using my friend's name to rent instead. When returning the car, they pointed out a very small dent and demanded £200. Such minor damages are easy to miss during pickup. After a lengthy argument, they finally dropped the charge. I bet the next person will get scammed too.

Counter staff initially told me I had no insurance and convinced me it was because it was booked as for US based folk and they had it on cards and did not need it. Luckily I realised that my booking said I had and pointed it out - I had passed over that info

ok

The longest wait and an error on my part cost me 4 times the original quote but there was no compromise on their part.

Car category I booked was not even available at the location. Told by counter staff go and complain to ACE. Given a completely unsatisfactory vehicle instead.

ACE London Heathrow branch is actually Greenmotion company which I believe they are partner and Greenmotion run service for the ACE. Therefore the service is similar to Greenmotion. One thing incorrect is I did have to pay for shuttle bus fee, which did not correspond to the voucher mentioned shuttle bus paid.