Which one is better

[FFuser]

I agree with you thelusiv.
On one point your are wrong: The source for racer is not available anymore (only for the latest stable which is quite old). The maker is not releasing the source for new stable versions (if they are coming out ever)

Things I like in VDrift over racer: opensource, more releases, good linux version.
Things I like in racer over VDrift: better steering with keyboard, more cars tracks.
Things that needs to be improved in VDrift: racing against AI (hard I know), career game.
BTW: since some things make VDrift unplayable for me (most important: I have no good graphics car to run all tracks well) I race in the good old Sports car GT (best racing game ever)