Well I think we all know how I feel about Owen....
Hedonist - yes, absolutely
Control issues - Ho yeah baybe
Most complex character - certainly looking that way at the moment, but then sorry, character development hasn't been great so far (Sorry but Ianto's "you don't understand I LURVE her, waaah waaah waaah" doesn't count.)
Adrenaline junkie - guessing so, hence the snog

I think we have also to recognise that love or hate him, the way Burn Gorman portrays him is sterling and he is acting his way off the screen in every ep.