Windows: A car with everything welded shut and you can only buy MS Gasoline and MS Oil.
Other Linux Distros: You can run any brand of Gas or Oil but your parts all come from the same company. You can tinker with the engine (compile your own software) but it voids your warranty. It comes with leather seats but they don't match with the rest of the interior.
Gentoo Linux: The car comes to you in pieces and once assembled, you find yourself constantly tuning the carbs, checking exhaust back pressure, tuning mixtures. You can choose any kind of seat covering, but if it is leather, you have to shoot the cow yourself. But perhaps the car is easier to drive and add new parts.
(from Gentoo Forums)