I don't know too much about either brand, but I'm pretty sure Digital Audio is owned by Audiobahn, not sure of the build quality of their products...I think Kole Audio is owned by Power Acoustik. Hopefully that info can help ya.
Digital Audio is a branch of Audiobahn and is almost identical in what they offer and quality. I previously had 2 10" DA DALUM subs and a DA 2200 amp. I was very impressed with the amp.