What about Barrichello? There were times when he was quicker than MS and occasionally he was even allowed to win. Both he and Massa learned a lot from MS however - that has to be admitted. The difference in Massa after a year of listening to MS is pretty amazing.
I disliked MS from the moment he deserted Eddie Jordan's team to go to Benetton but I have to admit that the guy could drive. He proved it often enough in his early career and it showed in the wet too. It's true that he never had a team mate of Kimi's stature (although I'd have loved to see him and Johnny Herbert at Benetton if Johnny had never had the accident that screwed his ankles - Herbert ran him close enough for me to think that the pre-accident Johnny would have rubbed MS's face in the dirt). As a result, it is very hard to assess him against others such as Hakkinen, Raikkonen, Frentzen, Alesi, even Hill.
But I don't believe his name deserves to be mentioned in the same breath as Senna's...