I have owned several used BMWs over the past several years. I have yet to buy a new one, besides the fact that I can't afford a new BMW, I probably would never buy one new anyways.
This video details the various reasons why I recommend used BMWs over new BMWs in pretty much all circumstances. Even if you have the money for a new BMW and you don't care about the depreciation, I still recommend that you lease instead of buying new.