Recently did premium on QF A380 Syd-Lon and return. Very pleasant. Drinks on seating. Nice food. No sitting around for hours waiting for your tray to be collected. Lots of room. Reasonably access to toilets. Sitting in the seat I could only just reach the back of the seat in front and could only just get my feet under the seat to the back of the front of the next one. I'm 180cm / 85 kg. Laptop power not working on the trip out. Not quite as comfy as Business but a lot, lot, lot better than economy. I just have to think of an excuse for the next work trip ...
Michael
EDIT: Forgot the only downer. Your screen is in your arm rest so has to be stowed on landing so you can't watch the landing from the camera in the tail which you can in economy. I did that a few months back into Heathrow and it was really amazing. But not amazing enough to make up for the other 24 hours of claustrophobia.