I've got a pre-facelift 2015 model - registered in March 2015. Prices go up after the new shape came out in late summer that year, but realistically it's mainly cosmetic differences. Mechanically and electrically they are the same otherwise. The battery warranty (in the UK at least) changed on 1/1/2015 though (gained an extra couple of years), so that might affect prices slightly. However many 2014/2015 cars will have done more miles than the warranty covers anyway, so remaining Mitsubishi warranty might not be relevant anyway.
Mine is an ex-fleet rental, just coming up to 60000 miles, and although I don't have a report from a Mitsubishi dealer on the battery state, I manage to get around 8.7kWh in when charging from the battery bar shows nothing (actually about 30% real charge left in the battery), which is good enough. I've had no issues at all in the 6 months I've owned it other than having to bend the charge port flap slightly so it doesn't catch the paintwork.
They did drop the lovely pale blue paint colour at the facelift which is a bad thing in my opinion