My 13" Air is a 2012, and its hanging around sometimes. I bought my wife an HP Elitebook 13", and it has a lovely keyboard which is waterproofed (or is that coffee proofed), a nice touch screen, and that screen folds 180 degrees so it becomes a heavy pad. It has touch ID, camera ID, and it doesn't insist on two IDs (like Apple have just done to me and I think the new Macbook Pros will insist on this duel password crap). While Windoze sucks I reckon I can get used to it. I couldn't get my wife's iPhone to connect to her Elitebook - but I left it a day and sure enough there's a settings page and it worked just fine. But instead, I'm getting a SIM for her notebook - yep, it has a cellular slot on the side. Plus old USB, plus Thunderbolt 3, plus large card slot (no idea what that is floor but it holds a Wacom touch pen (which my wife doesn't use), but also, its got a photo card slot too, which is really useful IMO.
OK ... do I drop Apple (still got my an old 5.1 Mac Pro with a calibrated Japanese monitor and its now running at over 3.6 Mhz with lots of processors and lots of drives. Scared to give up that beast and also if I print a photo on my A2 printer it comes out just the same as it looked on my screen. Exactly the same ... I still think that's a miracle.
But ... if I stay will Apple, if I buy a 2017 version, its quite costly. Plus, I'll have to add a port device which will give me connections. So I'll need to not loose that device. Plus it costs extra. Plus it won't be as reliable as the ports in a 2015 Macbook pro. Because Apple doesn't bundle such a device with their all Thunder port machines. They should you know.
I also rest my arm very near my wrists on the either side of my touch pad. And I love a nice keyboard. But also - I'm an ex dinghy sailor, a decent one too, and I can still do push ups on my fingers. I've got toughened hands with short stubby fingers and I hammer keyboards. The "A" key on my 2012 Air has lost its text - I wore the text off that key. I've gone through Apple keyboards on my Mac Pro. Curiously though, going through keyboards only started to happen with the alloy keyboards. Those all plastic jobs were tough IMO. I suspect the new 2017 keyboard is not so tough. And the 2016 is probably just a bad design.
People here talk about performance. But the 2015 with a higher card, is pretty much as fast as the latest 2017 with one of its highest spec cards.
The thing I like about the 2017 Macbook Pros, is that they're lighter. But the reason why is less slots, and a mid 70 capacity battery compared to 99.5-watt one. That's where the weight went. The 2017 is cheaper to build. I get the feeling though that the reason Apple don't put a 4 processing CPU in a 13", is beause they want you to pay a lot more. Same too goes for no separate GPUs in a 13". Can't help but think a bigger SSD is going to be much more useful to me, than a smaller one on a 2017. And I reckon the touchpad won't get in my hands' way with a 2015 setup. Plus I like its keyboard, and its a tough keyboard too.
I reckon the 2015 is a better machine, at the end of the day. If they put today's CPUs in it, and a thunderbolt three port in it as well, it would be a better computer than the 2017 model, although heavier. Leave the trackpad as it was. Have an option of a touch screen too. My wife loves her iPad, but couldn't handle a notebook at all. She loves the HP because its got a touch screen. Make that an option on the 2015 Macbook pro with today's CPU and a thunderbolt 3 port. A notebook with the ports you need is a user friendly device. Why pay more for less slots?