Smoker is the best Vice Admiral, of his generation.
He is a very open minded marine and is able to work with his enemies for the greater good. He's a large part of the reason the PH arc ended successfully and the Strawhats are where they are right now, because Law got his heart back.
2nd is Garp, as far as captures go. It's assumed he has more because he's stronger and older.
3rd Mamonga. Haven't seen much of him, but he has a very likable personality.
4th Bastille because he dropped the ball hard.
EDIT: OP, you need to make it clear if you're talking about power level or all things considered in a character.
Power level wise Garp, and this thread is stupid because of course it's Garp.
But all things considered, Garp and Smoker, but Smoker because he's had more relevance to the plot. Garp raised Luffy for a while which did contribute a lot, but Smoker helped make one of their adventures successful and saved Laws life.