In my opinion, AIO's have poor reliability. If pump dies and you away from your desk you doomed. Also, most of them have louder pumps, not really intrusive but loud enough that you can hear it and sometimes it can get on your nerves
Air cooler like Noctua for example, and if case size would allow NH D15S is superior and even thou I have custom dual loop only because of my 4 bloody hot GPU's, otherwise, If I had 1 GPU I would go totally air.
My son has NH D15S in his PC and its absolutely fantastic, he loves it and would not trade for any AIO.