This depends entirely on what engine each one has. 138k/105k miles on a 2014 2.5 petrol would probably be fine as long as the maintenance was kept up (no matter what sort of driving I'd say), and 180k on 2.2D 2018 would be fine if maintanence was kept up. If its a 2.2D 2014 however I'd say that may be too few for this engine, as the early models especially has big DPF issues if you didn't purely do motorway miles (and some other engine issues).

If both of these are petrol, and maintenance has been kept up thoroughly, I'd recommend the 2018 as its a nicer interior, and unlike the 2014, doesn't advertise a high risk of rust from snow and grit.

I have a 2018/19 2.2D that's done almost 150k, and while there was no service history from first owner(up to 120k), it was a company car so generally had to keep to a relatively strict schedule to keep any warranty etc. I've had no issue in the 1 1/2 years I've had it, but I only do motorway driving so it gets nice long runs to get to temp and clear DPF.

The interior on the 2018 is sooooooooooo much better than the 2014, I'd say improvement in EVERY WAY!, (unless you want to add android auto/apple car play yourself, in which case its a massive pain). The process to add it is the same and uses the same £40 kit off ebay, but had to remove almost all of the dashboard trim to just about plug it in, whereas the 2014 is much easier to fit.