My company has already shopped around in the US and now has all 3 agencies... sadly for Europe we're still all stuck with an exclusive deal with Hertz till 2010.... lets hope after that we switch away too.
As an example, about 4/5 of my colleagues pick up a car from MANchester in the UK each Monday, around 9.30-10am (peak times). Now there appears to be one overwhelmed agent (even the 2 they had previously had too much work), limited number of drivers to deliver the cars and everyone has to wait between 30mins-1hour to leave. Ridiculous, makes everyone annoyed and there doesn't seem to be a need. I complained, and as a PC they seem to have fixed it so that I always have my car immediately, but, still have to queue to talk to the agent. So many first timers in that queue just ring up their travel agencies and switch to Avis next door which has 2 agents, even though quiet, and get a car before the Hertz one they've booked, either that or complain about ridiculous! I saw one Platinum asking for the manager's number as he had no car and had to wait for 30mins too.... he was treated just the same as any other customer though... not a good idea!
Thanks for the interesting article link!