The best one I've tried was EBS' Multi Comp. However I'm geting major GAS from T-Rex's Squeeze! Tubes.........
In fretted bass I like to use a lot of compression because of the technique I use. Like Eric Langlois and Alex Webster I use very low action and strike the strings with lots of stregnt in other to get that "fret slap" in the tone. It really helps you get thru the mix. However when I play fretless (very rare, I don' have one right now, lack of money) I don't like a lot of compression, as it allows my to have more expression with my technique.