Late to the party but here's my experience.
I was ALL SET t to lease for 36 months. The way the CA presented the numbers, it appeared that I wouldn't really be paying much extra for a lease over buy, when comparing similar time periods.
And then I discussed with my accountant, who in 10 minutes convinced me to pay most of it out of pocket and finance a small amount for 4 years.
So, I guess numbers can be twisted either way, depending on which rationale you are using.
Finance rates are certainly much more attractive than BMW FS lease rates.
But if you prefer new wheels every 3 years, lease is the way to go. I like 4-5 year cycle so buy made more sense.