Believe it or not. I just rented a 2018 M4 yesterday. The air conditioner was not so good. Both my wife and I think her 2010 M35X air conditioner is much better....
Actually all the ACs in my Nissans except Primera(P11) built in UK are better than that M4...
PS: All my Nissans were used cars when I bought...
In fact my wife's M35X AC was not cool in spring 2017. Then I bought a AC Pro as below and recharged it. Guess what? It's still as cold as ice this summer ....went through 3 summers already and get colder and colder every year. I think it should be still OK next summer if not colder AGAIN...
And except that UK built Primera that's only AC problem I have ever encountered on my Nissans IN MY LIFE...
PS: I did not really like that Primera... So I sold it one year later and that's only Nissan I didn't like (I think that Primera was still OK. It's just not as good as my previous Nissan)... My other Nissans are 1998 Altima(built in USA), 2000 Maxima(built in Japan), 2007 G35S(built in Japan), 2010 M35X(built in Japan).
You may ask me why the AC can become colder and colder...
That's because I knew there must be a leak in M35X AC. So I overcharged it a little on purpose... (Because overcharging will increase more load on your compressor and AC cooling temp will also be higher... It may NOT be good for your car especially in very hot summer in Taiwan)
PS: If not colder next summer, it means R-134a finally reaches the correct amount... Then I think it should be able to pass at least 1-2 more summers or maybe even more... Who knows...