I think one question that I've seen about the lease buyout is where will you get the money to do the buyout? imho borrowing it is a bad idea--now you've paid the leasing co. to use their money, and you're going to pay a bank to use theirs as well, and you could be potentially be financing the car until it's 8 years old (I have seen that on this forum). In general, the interest rate is much higher for a used car, than new, although I belong to two credit unions where the rate is the same.
What I've observed is that some people are wheelers/dealers and if they want a 2011 550i stick, they figure out how to get the money years in advance, be it push for a better job, make this or that deal work for them, etc. They never seem to lease. My buddy who saw me get the 2007 335i coupe in 12/06 is a good example--he waited all this time and finally got a 2011 550i stick. He's not thinking about replacing the car already in 2-3 years, and his downpay was substantial such that his payments are barely over $400. Personally, I like his method, be it a Sonata, or a 911 Carerra 4S, doesn't matter, principles are the same...