I received my Boden Prog 5 last week and had the opportunity to play it out after having it one day.
First impression is very, very positive. Our sound man is also a bassist, and I've played a few with him at the helm (Bongo HSP 5, Dingwall ABZ 5, Sandberg TT4, and a customized G&L L2500).
He was floored with how good it sounded out front. Clear, articulate, powerful. I have to go by him as I use in-ears with this project. While it sounded great with those, the true out-front sound is hard to pick up.
Felt great to play. I played the Dingwall so the fanned frets weren't a big deal for me to get used to. One of the reasons I wanted this bass was for the weight. I have some shoulder issues. It's like nothing is there. It's so stinkin light, but it still feels substantial, like there is an instrument there. The neck is really interesting. Took me a little bit to get used to the shape, but it is very comfortable. That said, I have very large hands, so your results may vary. I can't imagine you'd have much of a problem though.
The Norstrand Big Rigs with the Darkglass pre is phenomenal. I really love it.
I think the only thing I was a little disappointed in was the finish. I think I would have preferred a gloss to really bring out the best in the flame maple top. Not really an issue, more of a preference.
This instrument will work perfect for my current project which consists mainly of more aggressive 90's grunge stuff (maybe odd visually, but sonically it's great). I have to wait a couple of weeks to use with more more subdued project, but with what I have found with a little tweaking of the knobs, this beast can be tamed.
I also found it to be VERY responsive to different plucking techniques and right hand placement.
All in all, I am very happy with mine. I might even name her! Never did that before.
Sorry I have no experience with the Keisel models. I have heard good things about them, but I am not a big fan of their pickups or body shapes.