I've been intrigued by the design for a while, too. My main interest is in utility knives, I only started looking into self defense oriented ones recently, so I got a couple of the Graham brothers Razels to check out a while ago since a friend that had one raved about it. Since I sell knives, I often just get something to check it out and I can just put it up for sale if I don't like it.
The Pocket Utility Razel was quite nice, decent size and sharp. This guys are good, fit and finish was excellent, the handle was really comfy. I decided to keep it, but after the novelty wore off I started carrying it less and less. It's a good design, but I don't use a chisel that often, and I carry multitools constantly so I only need my main knife to cut, that's it.
The Stubby Ringed Razel I tried out was not as useful, although it was equally well made it just didn't have enough of a cutting edge for my needs. Being a kerambit freak, I loved the ring, though.
I'm very fond of sheepfoot blades for utility work, so I love a straight edge and don't mind having no point, but I just never got used to that chisel like edge (it's ground on both sides, though) on the tip. I have no real use for it.
My feeling is that this knife appealed to a lot of people who use their knives for non-knife chores and kept snapping the tips off, or collectors who just liked the shape.
If you feel like trying one out, try to find one of the CRKT ones for a good price (the ringed one is nice for about $65). Just keep in mind that the custom ones by the Grahams start at around $200, for a handmade knife with Paul Bos heat treated 154CM blade that's a great price.
Another advantage of the design is that it's quite sheeple friendly. I'm always doing repairs around the office (I can't sit still at a desk!) and some of my knives raise some eyebrows, but nobody minds the CRKT Ringed Razel I've been using as a beater. If you want I can try to write up a sort of review of that one.
Sorry for the rambling, in a nutshell, in my very personal opinion the "stubby" ones are glorified chisels, the ones with blades in the 3" area are actually quite useful for everyday stuff. The bigger ones and the folding ones just don't make much sense to me. The original design, a pocket utility fixed blade, it the one that works best.
Let me know if you want to know something more specific, I just love talking knives.