I personally prefer large. Units on huge I tend to find are simply too unwieldy for my liking, whereas on normal there often aren't enough men on the field to make for interesting battles. It's true that the EB scripting is more geared torwards huge (as otherwise the AI gets 100 population dumped into its settlement for every unit it recruits, as, IIRC, the AI gets 200 free population for every unit it recruits), but that's just fine by me. Bigger cities are harder to keep under control once conqured anyway, which adds to the challenge.