Reviving this thread as I'm flying this week MSP-AMS on A339. Seatguru doesn't mention the bigger footwell for row 1; it only warns against galley noise. Also, some mentions above about the seat being next to the window in even numbered rows, so 2A might be preferable to 1J for that reason. Both seem to have some positives then.
Anyone with thoughts on 2A vs. 1J?