I was in the same quandary, went with a 64 GB iPad pair with LTE. Already had an extra apple BT keyboard so with the appropriate origami case, I get a very configurable setup - amazingly light tablet running necked when desired or grab the keyboard and have a pseudo ultrabook if needed. I am hanging onto my 2nd gen 13" MBA because I love it and it still works as well as the day I got it (actually, maybe a smidge better with Mavericks). But for 1 mobile device? I'd get the iPad with integrated LTE and still save some money as I configured above.