For soloing? For the bridge position the Hot Rails might be the hottest if that's what you're after. But I prefer the tone of the JB JR.
In the neck position The JB JR. neck model is hotter than the Little 59 but I prefer the Little 59 because the chord tones are clearer. The Duckbuckers are pretty popular in the neck and middle position too.
Jennifer Batten uses two Duckbuckers and a JB JR. in her guitar...the one she plays when she performs with Jeff Beck.