Who do I like more? Ken Griffey, hands down. I think we forget already how much fun the guy was...from his smile, laughing, hat backwards, etc. He was a kid out there and so much fun to watch. He was a stud and put together an amazing career.
All that said, Barry Bonds, and this is pre-roid Bonds, was arguably one of the most talented players to ever play. He was a great defensive player, great baserunner, great hitter...he could do it all. Griffey was a good to great defender, but he never was a great baserunner/stealer and he always struck out more than he walked. I think you can put Bonds from 1990-1998 up there with anyone.
I'd probably take Griffey because I don't think the talent/skill level is that different and I like him more, but just based on numbers/talent I have to say Bonds.