I would have to say Sasuke. Sasuke had to deal with once having something to losing it literally over night. He also had a 7 year bond with his parents and also his brother- Naruto never made this bond even though he wanted to have the bond.
Yes, Naruto was hated and Sasuke was "loved" but really Sasuke was only liked by the young female population. Even though he got attention from them, there feelings were just dumb hormones, not really true feelings. As they grow older this does change, really only with Sakura and maybe Ino, but otherwise I see the feelings as worthless considering most of the girls liked him for being cool, attractive, an Uchiha, etc.
Teachers and other adults 'liked' Sasuke only because of his abilities as a student and as an Uchiha. Which they may not have been as interested if it wasn't for his clan/brother. Even so none of the other adults really show 'feeling' to Sasuke, where as Naruto does make a bond with his teacher Iruka and maybe even Kakashi later on.
Therefore, I feel that Sasuke suffered more. He went from having parents and a loving brother, to not having them in one night. He had 'fans' but none of them really cared for him like some did for Naruto (Iruka, Hinata) even if Naruto didn't realize it at the time. We also need to remember that Sasuke lost more than just his parents, but an attire clan and family- Naruto never made this type of bond until later in his life.