GERT can't deterministically service interrupts, but it's technically because of the armv7a architecture and its non-deterministic generic interrupt controller. Also, unless your Go program is constantly creating and destroying objects, the garbage collector won't really run. I wouldn't put GERT on my ABS brakes just yet, but I think you can engineer around a GC.

I wish there was an armv7R or armv8R dev board around (that doesn't cost thousands) because those are actually meant for realtime applications and I would really like to try GERT on one.