SIM switch doesn't concern us currently. We use the RUTX11 failover as:
Primary WAN: wireless client connects to our network when vehicle is in premise
Secondary WAN: 4G when vehicle is on the road
Be great if the radius server could be a radius group containing radius servers (for redundancy) or to be able to specify a secondary radius server. But hey ho, it's on this firmware (yet to test) and the firmware seems to have sorted out some other bits within RMS