If you mean freakishly ugly then i'd take missionary but if it's someone who is called ugly by lots of people but really isn't then i'd take them instead.
A fuck with your favourite porn star knowing that you may be nervous and also get judged and laughed at if you are bad
Or
A fuck with the hottest girl in your area that is the same as every other fuck you've had except with the hottest girl.
An average looking girl all to myself. Its one thing to watch a gang bang, its another to actually bump uglies with 3 other dudes, while banging a chick.