Personally I'd have a look and drive them all as you may just find that one car feels a lot better than the others. This can often be the case with lease cars as they can either be abused in a fleet or they can be the sort of car leased to a particular person who looks after the car well. Some cars with the same mileage will feel vastly different.
I know every 2nd car is a focus but when you're behind the wheel it's a shockingly good car to drive. It just does everything so well.
Good luck
Good advice, we have about 10 focus's where i work from 07 to 09 plate. Some are complete dogs where others feel spot on. I have found the build quality differs massively in them as well as bits are falling off the 08 plate i was driving yesterday...
Only problems i have encountered are, turbo hose comes off when driven hard (thrashed) steering column can come loose so steering wheel slides forward under heavy braking(not fun at 120mph), i have never been very impressed with the brakes but that's another story.
Reliability wise they are superb with only one engine dying (32000 miles it expired but it never felt right from day one) in all of our cars in the last 2 years.