the Supershinn is stiffer, longer and it has a straighter outline with wider tips. For this reason you won't find another board in the Shinn line up with more "Pop". It is a high performance board which is easy to use in every kind of conditions. Compared to the Monk it feels less nervous and a tad less agile. Depends on what your are looking for. If your board should offer the ultimate performance go with the flagship the Supershinn, if you don't care about jumping half a meter higher and be everytime the first on an upwind course because you go most of the time kiteboarding in good conditions(steady and strong winds) and if you like to play around and throw your board in any curve radius go with the Monk for highspeed and air and with the Dundee for carving in the waves, air and an even more comfortable ride.
The Supershinn offers also the widest stance and is still very comfy in choppy conditions.
All Shinn boards are excellent boards above average go with the design that you like most.
Thanks so much for all the info, still can t seem to narrow it down , i do know it will be one of the three lol. The hard part is i like to do all the above. Thats why its so hard to decide!!! : Whitey