Okay
I sat in 35K on the way there, and 8C on the way back.
35K (and 35A) is probably my pick for one of the best seats on the plane. It's not classified as an extra leg room seat, so you don't pay extra. This is because the exit door is in front of you, but it's still got a lot more room than normal, and you get a footrest as a bonus! It is right behind the toilets, however there's bucketloads of room in front so I didn't notice anyone congregating there. The crew jump seat is in front of you, but again it's miles away.
8C would be my pick for WORST seat on the plane, along with 8H, and I am counting the middles down the back. This is the first aisle seat after the XL seats, and the aisle is askew - this means the FAs with the carts run over your foot or ram your knee every time they go forward-back. You get less leg room than a standard seat because you can't put your feet under the seat in front of you. So you can either twist your legs way to the window side, or be stood on and run over constantly. To make matters worse, you pay dearly for this "extra leg room" seat. Screw that!!! I can ALWAYS sleep on planes, but this time I was woken up every 10 mins by someone stomping on my foot (because I couldn't twist myself enough to get out of the way).
All of the bulkhead seats are narrower since the tray and screens are in the armrest. To help compensate for this though, the middle seats are very narrow and aren't "real" seats - they have a seat belt, but noone over 3yrs old would fit in them. This is why you can't allocate them, but are great to put your junk on (since there's no seat back in front of you).
In other rows, the armrests lift up. The seats are fairly flat so if you're lucky enough to get a full row you could sleep fairly comfortably.
I didn't actually get down the back to have a good look around there, because these were both overnighters so sleep was a priority. I can say though the XL seats look to be about the same as a standard QF economy seat - in no way worth the money (unless you physically can't fit in the normal seats, which many people wouldn't).