Inline 6s are some of the most robust motors out there. I've owned a couple of Slant 6 (225ci 3.7L) iron blocks in my early days and they would run even when they had a hole punched through their piston. I'd be down with a I6 if they made one. Only thing I'd worry about is fuel economy. It's the one downside of the I6
Indeed, they are incredibly robust and durable. If properly designed they are also very efficient. BMW's Inline 6's get great fuel economy.
The BMW 340i, 3L turbo inline 6 making over 300HP gets 32MPG on the highway. That's absolutely excellent fuel economy for a rather fast car.