Soy seems to be the most active image board right now but there's way too much spam and nonsense posting for me to bother with it. This place is looking like the best alternative to 4chan atm; decent thread/post quality and you can actually have a conversation, but the pace is still way too slow. OTOH maybe that's just the price you pay to not have jeets, bots, and JIDF shitting up the place.