I'm not an expert. Betadine (aka povidone-iodine) leaves a reddish residue. I've read that the residue provides some lingering antiseptic value. I've also read that it's not flammable, which would explain why they like it so much in operating rooms. Finally, I've read that it isn't appropriate for long-term wound care as it may inhibit clotting. You can also use it to disinfect water.

BZK doesn't leave a residue, which might be better or worse for you. It's at least somewhat flammable, and I wouldn't try to use it to disinfect water.