In reply to ClarNicG:
Used Locauto last week. Were highly rated online, terminal pickup and not too expensive. Would use and recommend again. (Milan airport)
Earlier in the year I used Interrent which I think is part of Go rent.
Tried to rip us off on drop off for the tiniest scratch that was already there. We took pictures of everything before hand but still had an argument for 30mins
Locauto had a staff member present to walk around on collection and pickup whereby the cheap ones don't unless you drag them out from their behind their desk.
Hope this helps
Post edited at 18:15