I went on an A350 a few days ago LHR-MAD and then on to MVD on an (old) A332. I found the A350 seat quite hard and uncomfortable in the upright position. Fiddled with it a bit after takeoff (not all the way to lie flat) but could not get totally comfy. Fortunately it is a short flight. In contrast the old A322 seats were much better for me (and slept OK too). YMMV.