I very rarely download porn with condoms in, and it would need to be a damn good film for it to stay on my drive.
As for boner killers, obviously everyone has a particular type of guy that they like or dislike. What I've found is that there are quite a few performers out there who, despite matching up with what I'd tell someone I find attractive, instantly make me delete that film forever. I can't quite put my finger on whether or not it's their acting ability or what, but seeing them on screen can totally destroy a good wank.
I'm thinking of actors like Denis Reed, Michael del Ray, Johnny Rapid... Even Joey Mills, who I quite liked in his time at Helix, but always seems to be phoning it in now at MEN. When I see any of them (or a number of others) I just know there's going to be no chemistry, no passion, just someone going through the motions to get a paycheck. I know that most porn is done for money, but if you're going to earn a living that way then try to make it more believable than your local amateur dramatics company attempting to perform Hamlet.