Exit row is excellent. Not only do you get more leg room, but on many planes the seat in front of you doesn't recline.
As for the risk of fat people, just make it clear that the arm rest stays DOWN. If necessary, we'll get one of the flight attendants to jump up and down on it until it's all the way there.
On one of my most recent Portland-DC direct 5 1/2 hour flights, the last passenger to board was a 500 pounder -- at least -- carrrying a huge "carry-on". Of course, it was a full flight. There was not a square inch of bin space left, but he claimed that his giant carry-on had his insulin in it so it he couldn't possibly check it (and, conveniently, he couldn't just take the insulin out and check the rest). The flight attendent then informed him that the only seat was a last-row, bulkhead, center seat. He started to protest about how he had an assigned... and the flight attendent informed him that he was late. Reserved seats are given up 15 minutes before departure, they were late to take off, he was delaying the whole plane, the pilot was furious, air traffic control was mad, they had just spent five minutes dealing with his luggage, it would take five more minutes to get him belted in, this is your seat so sit in it! And there he sat for five and one-half hours. Had he not been a guy, I would have kissed that flight attendent.