Allthough you said screen: the bigger the better,I'd like to mention here that the Xperia Z Ultra is a nice device.
It's the best in terms of looks, the Snapdragon 800 processor with 2 GB RAM will be more than sufficient for any apps/games, waterproof aspect helps if you're on the go, full fledged SIM slot ( many SIM tablets have the call abilities disabled like the Nexus 7 )
6.4" might seem small but it's good enough for reading/videos as well as saves battery. It can also be used single handedly, unlike 8" tabs.
I got it because i travel a lot on trains and bus, one handed helps while holding on the rail standing. The glass surfaces will give up if you drop it though so not so much on the ruggedness part