We bought our M35i specifically to make road tripping more enjoyable, and it hasn't disappointed at all. Personally I love the hidden trunk compartment where the spare would normally go. Anytime we park some where remote or at trail heads, we put all our valuables and personal information in there. I just leave the glove box and center console empty and open when I leave the car, so anyone looking inside can already see there's nothing there.
The Eco Pro drive mode is nice if you're just doing long miles on boring roads, put it in cruise and save a ton of gas. Though I pretty much only drive it in sport anyway because I'm weird like that.
It has a big gas tank too, which is nice for a car with this much power.