It's brilliant. Seriously good, pretty stable, not encountered any bugs. has a feature called "drop in". You can set it up so when you are battling in the campaign map, some random will be the guy you fight in battles rather than the AI, or you can be their random.
The campaign map is yummy - im easily impressed as they get better with each iteration imho - lots of detail - even down to seeing scaffolding on upgrading buildings.
Im taking it slow and working into it without rushing or looking how to shorten/lengthen turns