Upgraded from 5 to 5S. Was the most useless upgrade I have yet made, as I did not notice any difference between the devices. My fingerprint scanner does not work, though. The A7 probably does, but I do not see it adding any value, since 5 was already fast enough, and the screen is the exact same panel as on 5, that is, blacks will be shown as greys on 5S as well and outdoor readibility remains a bottleneck. Seeing how fast the competition is moving, I was really-surprised Apple treated 5S as an afterthought and just did not bother this time around.
I donated my old iP5 to my mum, but she did not want to replace her Nokia with it, as she found iOS clumsy and cumbersome, and the screen too small. So I ended up selling it and got a good 300$ for it. Not bad. Though it was in mint condition -- no scratches or anything -- since I do not abuse my phones.
Unless iP6 does something truly magical, 5S will probably be my last iPhone for the foreseeable future, and I will be jumping platforms when the next upgrade is due. I will remain an iPad user, though, at least for the time being, as the tablet product line is actually competitive.