My impression of BDO seems to be different than most. BDO's PvE isn't innovative or anything, but the combat feels smooth, the world feels alive, and your character feels powerful while you kill things. The monotony of grinding is relieved by your ability to have workers, decorate your house(s), fish or explore. I would consider myself a casual MMO player and the immersion and enjoyment I get out of BDO is unrivaled. The part of BDO I'm wary of is the potential for P2W if the western release isn't changed enough.
I played BnS on Russia and hated it because of input lag. I have a master pack and have played some in the alpha/beta for more BNS Gold. To be honest I still feel like the combat isn't as responsive/smooth as I'd like from action combat, though the moves themselves are fun to use. The PvP is addicting. Really so much fun. The leveling bored me sadly. It felt slow and repititious. The few dungeons I did were fairly fun (not as good as Wildstar or FFXIV though imo).
If you feel like you are the kind of person who would be casual in the sense that you'd log in, do a couple dungeons and/or some PvP then log out, BnS can offer that. If you are the kind of player that logs on, and wants to do more crafting/fishing/trading, kill some mobs and feel more immersed, then I think BDO is better.