I still experiment a lot but so far, I like Arco, Aby and Miasma the best.
I play Aby when I want a fast start via a blood nation (occasionally BF Ulm but mostly Aby). Small maps, blitzes, etc. Not a lot of micro, not a lot of re-scripting mages, etc. but still effective.
I play Miasma because I like the potential for tartarians and the Miasma effect helps me get to them and can otherwise be a nice MP tool. I also like Miasma because I think they are a bit of a challenge (compared to Aby and Arc, anyway), due to their, imo, abysmal national troops. Otoh, I love marshmasters. I probably play Miasma the most, of the three, since I feel like I haven't *quite* got my finger on them yet
I play Arco (mostly default but sometimes GE) when I want to do well and have tons of time to script mages, complicated communions, teleports,, excessive artifacting, etc. I don't play them defensively but I think more long term with them (large or underpopulated maps).
I don't really dislike any nations except maybe dead Ermor(AE or SG), for reasons that would only spark a dead horse debate
- Kel