Well, argue what you want about the merits of boat designs. It really comes down to style and personal preference. The RPM is still my favorite boat, despite owning at least a half-dozen others during its tenure, and a whole bunch of other boats before the RPM came out. The RPM is a damn good (if old-style) design and it compliments my paddling style -- it's very fast, comfortable, surfs great and you can dump water from the bow when it pearls, punches holes surprisingly well, and the sharp rear chines enhance performance when it's on edge. Sure, I have a creek boat for harder water, and a play boat for the Poudre at 1', but the RPM is my usual go-to boat and all-time favorite. It's just plain fun to paddle, and just as comfortable as my creek boat.
Having said that, the RPM is a displacement-hull design, and is very asymmetrical. It's going to have trouble doing flat spins and the like, you really need to pay attention when it's sideways in holes, and the broad flat rear deck sometimes results in back enders at very inopportune times. So it's not for everybody - your boat should match your style.
Now for the real post: I'm still using an old PD Designs back band and have the same question: Has anyone figured out a good way to install a modern back band that offers better support, easy adjustment, and an easy way to move the back band aside to put in/take out dry bags? I've got a ratch-style back band from a Wave Sport boat that I'd hoped to install, but the seat/cockpit design aren't suitable (I haven't found a good way to solidly attach the ratchet). I'm going to take this down the Grand again this fall, and I want it to be cushy comfortable.
On the other padding: I shaped minicell for the hips and used adhesive-back pads for the thigh braces. These last about 10 years if you're careful getting in and out (and don't loan your boat to others ...).
