I was driving a '10 E90 335 xDrive auto that I was perfectly happy with, when I was at my dealer for a service I wandered across the street and found in the showroom an '11 E91 M-Sport 6MT (RWD) with 9k miles on it. I took a test drive, got out of my 335 lease early and bought it that day. I gave up 70 bhp and 100 lb/ft, but I honestly don't miss it. It handles better than the 335 xDrive did, and selecting my own gears (as Richard Hammond recently put it) is a form of self-expression.
The E91 6MT with M-sport or ZSP in rear drive form is a fantastic sports car, that just happens to have a ridiculously useful boot. I drove it to FL and back from Seattle this past February and brought my Golden Retriever along, had plenty of room in the back for his crate and all of my stuff.
I recently got the BMW performance exhaust fitted, and it has changed the character of the car, it now sounds as fantastic as it looks. Mine had the roof rail delete, I have a set of Thule Aeroblades that go up there if I need a rack.