too bad the Mamba outfitting didn't work out for you. Certain people with certain outfitting just don't work out. I have to say that personally I find Jackson's outfitting the most comfortable, with perhaps Liquid Logic's badass outfitting in 2nd place. Maybe the new dagger outfitting will work for you, we'll see. The new "leg lifter" feature looks awesome.
In the Jackson line, closest in performance to the Mamba would be the Zen at this point, although I find the Zen hull to be a more aggressive planing hull than the Mamba. The Hero series is also worth considering, although Hero/ Super Hero are going to feel more rockered/ "turn on a dimy" than the Mamba.
The Remix is a good option too and should be comfortable, but there is no edge and less rocker, so it will handle differently than the mamba.
Here's my Zen and Remix review:
Jackson Kayak Zen Review with Dustin Urban
Liquid Logic Remix 59, 69, 79 Review with Dustin Urban