Car hire - uhm, full of pitfalls no matter who you go with.

I usually use Avis from T5 when I'm in the UK and are generally fine. A couple of time I've had some rather 'worn' cars, other times with a few miles on the clock. I rarely do it through BA since the prices are no different. One thing to notice if it's done through avis.co.uk it includes all the insurance, through avis.com only the liability (which is compulsory in the UK anyway!). Check your credit card company for any insurance coverage - and avis preferred is the way to go (as is the Hertz Gold Rewards).

Having said that, Avis in the US is somewhat variable. As a previous poster has noted you book a car, turn up and they don't have it and try to sell you something much more expensive. But, stick with it and insist they the have to give you what you ordered - or better. A couple years ago I was gob-smacked by my daughter (then 22) who had booked a mustang - which they "didn't have", and she managed to argue her way up to a 6 liter dodge charger (which given her age should have been a no-no!).