Nice work man, but I'd recommend not fully assembling your guys before painting. With space marines the backpacks and guns (if they're carrying two handed weapons like bolters) really get in the way of the chest and back areas and make it difficult to paint them. It's not much fun assembling most of a model but not getting to see it fully assembled until it's completely painted, but you'll almost certainly get better results by painting some of the parts separately. Give it a try!
Anyway, I always like seeing Alpha Legion; I'll keep an eye on this thread!