http://forum.mikrotik.com/t/rb4011/122850/1
Many minor issues like reboots, freezes, SFP issues plenty of butthurt. I guess ARM devices also don’t support CPU clock adjustments. I also personally use hAP ac2 and I didn’t manage to get USB modem to work. The same modem plugged to CCR1009 works flawlessly so I ended up connecting 3g backup line to core router instead of edge router which doesn’t really make much sense tbh from infrastructure standpoint but it was the only option I had…
Basically ARM support is quite incomplete comparing to other platforms including Tile-Gx.