You can't recline the seat in front of the exit row - on the 777 even that is not a problem since there's a bulkhead or toilet in front of the exit row.

To the OP's question - as mentioned, seats in the exit row are narrower and I'm always annoyed that I turn on the overhead light just by moving. Historically I've found the number people congregating in the exit row (to stand up or to wait for the toilet) bothersome, so I have always chosen for Eco Comfort since.