I've got the z2. Great tablet. Very thin and light, and very fast and stable. Screen is nice and the battery is decent. Can't really ask for much more.
Drawbacks are the buttons at the bottom of the screen are too small and fiddly to hit, the battery while decent isn't as long lasting as the iPad air (But I'll let it off as you can do things on android that aren't easily possible on the iPad), and the quality of some android apps for tablets is lacking. Also the fact that some websites default to mobile mode can be irritating, you can request the desktop site in the browser but that's a pain to have to do it on every page you visit and it doesn't always work, the only cures if you can call it such is to root and force desktop user agent or use a different browser like Firefox or opera that let you do it by default. The latter issue is more to do with android than the Sony though.