I know Joker, Murray, Rafa, Fed are hard and tough to beat. They come back so easily and the lines wont move even if they are 1 set down and 1 or 2 breaks down. They are mentally so tough and dont give a chance to others.
On the other hand you have totally unpredictable players. They are so talented and so effortless in some of their shots and have a better chance of beating the top since they are mentally retarded in a way to get bogged down against mentally tough players
I count Fognini, Paire and Mr. Clown (Monfils) in this list. They could be worth a punt of over 10odds you can find on a unit, what do you think?