While I love my Nexus 4 and especially the, now discontinued, Nexus 10, the 7 is a piece of junk, IMO. I run the same software on all of them (actually, less on the 7), and I have to charge it as often as the 4, which I use far more and is also receiving a cell signal.
The 10 is pretty sweet though. I can get almost two weeks, as compared to one/two days from the 7, with similar usage. I've wanted to throw the thing away myself. I don't blame Ubisoft.