Good Fast People
Feynman was very fast. Once his mentor, Wheeler said, "Yesterday, Feynman convinced me that it went backwards. Today, he's convinced me equally well that it goes around the other way. I don't know what he'll convince me of tomorrow!"(source)
Traders are very fast, making dozens of decisions per minute.
Poker players are very fast too.
Fencers, boxers, tennis players are very fast too.
Good Slow People
Warren Buffet was very slow. His recommendation is just to make 20 or fewer bets per life.Warren Buffet has often said, "I could improve your ultimate financial welfare by giving you a ticket with only twenty slots in it so that you had twenty punches - representing all the investments that you got to make in a lifetime. And once you'd punched through the card, you couldn't make any more investments at all. Under those rules, you'd really think carefully about what you did, and you'd be forced to load up on what you'd really thought about. So you'd do so much better." (source)
Kazuo Inamori was very slow. It took him and 5 engineers and more for about 6 months to start KDDI, Japan's second-largest telecommunication services provider.
Lou Gerstner was very slow. In Who Says Elephants Can't Dance? , he took about a year to come up with a turnaround strategy for IBM.
Sir General William Slim was slow. It took him rounds of consultation to do a "Defeat Into Victory" in Myanmar against the Japanese.