Hi there. Sorry about that - I only realised one existed and that is the Dynabar, which I have "Dynabar V5.1 freeride" - I guess it might well be telling that I had never heard of either of the other two types of sliding hook you put in your response.
Not to say that they suck, because I have never used anything except the Dynabar.
Review wise - it feels like a totally normal harness when it's wedged in the little outdentation at the front. No problems or technique changes required to use it for normal twin tippery. I never had it slide off in a weird way during jumps or anything like that, but as soon as you start riding toeside, the fixing point slips nicely off to the side and allows you to add 10 or maybe 15 degress more angle upwind, without the unpleasant twisting you get from a regular harness as it pulls around your body.
The upshot of this is you can just ride the whole session on your happy side (I know Peter Frank will be upset with me for suggesting it but...) you no longer have to Jybe, or try to learn to ride waves switch stance. You just get the kite up and roar off into a wave-riding frenzy.
I have quite an old model and I am sure that the old saying "Moving is just another way of saying 'not broken yet'" is completely true, but I have only had to replace one part and that is the plastic sheeting that covers the main hook attachment. This is sort of designed to wear down, and they send you a full set of replacement parts with the kit. Quick and easy job to fix when I noticed it was worn through.
Although it has never happened to me, or anyone else I have known, I guess it is possible to get your finger's caught in front of the hook as it slides, and the consequences of that would be really horrible I reckon, but you'd have to work pretty hard to make that happen - and from the first time you ride it, you'll realise that pro's massively outweight the cons.
Hope that helps.