I'm sure Skippy doesn't taste much different, but I have always gone with Jif! It's what I've eaten my whole life, and there's no reason to change now unless someone I knew told me that Skippy was so much better... but that's what the people I know say about Jif, and I don't believe they could be all that different anyway! =)
Both of those are smooth. I wouldn't eat smooth peanut butter. Only crunchy.
You know, both of these brands do make a crunchy version too! =)