I had one... For an extremely short time as it was returned.
Camchain so no need to worry about changing it unless noisy, just make sure it's serviced every 10k or so!
Mine had a low noise when foot came off clutch between 2nd and 3rd, two friends do the same so wouldn't worry if you hear it!
The sync for reverse isn't particularly good, it will give slight resistance/grind, Google it and its normal. In the 2018 it's the gen3 of that engine, same as I had in my 17, they're pretty robust engines, can't think of any real problems!
On my 2013 diesel I had the fuel cap jam shut and then the 2016 1.4 did the same, so Id recomend having the solenoid changed either way for the sake of £30 or so as they had to snap it open both times!

other than that, I've only had previous owners taken bad care issues on all my leon