Did you "learn more about him", or become victim to some sophisticated campaign against him?
The people who run campaigns, on both sides of the isle, are very adept at trashing people, whomever they are. No politician is as bad, and none are as good, as they are made out to seem.
I have disagreements with Rudy. But he is a vast improvement over Hillary, and taking steps today that will hurt the chances of defeating hillary in '08 is not a smart thing to do.
In particular, "making up your mind" on Rudy today is not a good idea for conservative values. Vote against him in the primary, but have an open mind that he's not satan and it's OK to vote for him next Nov if he's the candidate.
You have already made up your mind but you think others do not have the same right.