With the advent of ultraportable laptops a few years ago, I've almost entirely stopped using my tablet(s). The upsides of a smartphone's form factor are self-evident, but a suitably light laptop is (IME) so far superior to a tablet in comfort, usability, and efficiency that the category has been practically obsoleted for me.

My current laptop has a 13 inch screen and roughly the dimensions of an 11 inch macbook air. There are very few times I find it less convenient than a 7 inch tablet, and almost none compared to a full-sized tablet.