Yes the AC will be better WiFi, but it’s more on the rest of it.
I have both and will be installing in a job soon whichis residential with lots of apple devices and 8 WiFi points around the home.
I don’t need the WiFi on them for performance, just as the backup in server rack.
How are the two performance wise? Do I need to cut some slots in the ac2 due to it feeling hotter when I leave both on?
hAP AC runs cooler with its vents.
Why not go with the rb750gr3? It has nearly the same wired performance, rock solid stability, is cheaper, and runs at near ambient temperature.
Not much availability of that in UK.
Also I have a hex s , I need the WiFi though.
You are not serious?
Didnt you check out the specs… the hapac2 is a 4 core unit with hardware ipsec, the hapac is a 1 core unit.
Thanks for the info, I have got a little confused by looking at price.
Ok
HEX S - 2 core and this has SFP https://mikrotik.com/product/hex_s 385 megabits WAN to LAN https://mikrotik.com/product/hap_ac2WAN to LAN
hAP AC - 1 core you mention, Wireless AC and SFP https://mikrotik.com/product/RB962UiGS-5HacT2HnT 318 megabits WAN to LAN
hAP AC2 - 4 core and AC Lite https://mikrotik.com/product/hap_ac2 986 megabits WAN to LAN
is for routing performance the hAP AC2 is best of these 3? But it is the lowest cost 
hAP ac2 the newest of all three. Surprisingly prices of MT gear don’t get lower when newer devices in the same segment get released… however prices of new devices are set according to market state at the launch time. Hence the weird state where older and less potent devices are higher priced than newer ones.
The moral of the story: with Mikrotik suggested prices shouldn’t be taken as selection criteria, they can be only taken as elimination criteria.