nexus7 2012 v nexus 2013. i prefer the latter but in comparison there is little visually to seperate them, though the, 2013 model is marginally taller; marginally lighter in weight; it has higher screen resolution and a 'back' camera.
price is maybe the largest factor if there any more stores that are stocking it as argos has not stocked it in our area for a few months, now.
Ideally, it has to be the nexus2013 with the latest 4.4 update.