I've never been on the A350, but I love the A330 seats. I'm 6'4" (only 200 pounds though) and they are one of the few J seats I've flown that I feel I really fit in. From what I've read about the A350, the seats are a bit smaller. If you need space, go with the A330 - don't fall for the marketing hype of the A350. As I said though, never flown the A350, so others may contradict me.