Hmm, it's hard with my two. They're both the boss in different situations.
When they were bonding it was Pipkin who was mounting Ruby, so he seemed to be dominant then. He still occasionally tries chasing her around the garden but isn't as persistent as he was at first.
Ruby is boss of the food. She sometimes steals food out of Pipkin's mouth :| Occasionally he steals it back and stands up for himself but usually just goes back to the food bowl.
Pipkin is boss of the snugglesafe when it's cold. He gets to sit right in the middle, Ruby is only allowed to rest her head on one side :roll:
Pipkin is also the boss of groomings. Ruby always complies when he asks for it but if she's asking then it's pretty hit or miss. Pipkin usually ignores her completely..
So I think it's probably pretty even... maybe Pipkin is a bit more dominant. I think he loves Ruby more than she loves him, though.