An oiled one will always outlive an oil free one. The oil free will need no maintenance, but it'll pack up sooner. If you do very intensive work (ie, spray painting large objects, or anything else that uses a reasonable amount of air) then the oil free will pack up much sooner.
If you're sure that you'll only be pumping up the odd tyre and blowing stuff down, then you buy whichever is cheapest. Normally, that means oil free. If you think you may go down the route of using it for longer jobs and with air tools, then get an oiled one.
The key thing is to think about the duty cycle – most home compressors will throw out 7CFM or so. Most air tools consume air at at least that rate – a spraygun needs 14CFM, a rattle gun needs 5CFM). So you end up with a compressor that is running most, or even 100% of the time, rather than running for 30 seconds, then cutting out for 30 seconds on a 50% cycle. An oiled compressor will bear that kind of work a lot better than an oil free one will.