I believe that the Dubby is the first of its kind to be marketed, It came out in 1986 or 1987, I bought mine in about 88-89. Other then some rust on the sliding stop, the thing still looks new.
Many have made copies, and a few may even be better. I like the Jointech one, but with the indents at 1/2* marks, it could make it difficult to make fine adjustments between the indents.
If I were buyine new now, It would be either the Dubby or the Jointech. I don't like the Incra at all. It just don't look like it is designed the best it could be. But it would be my third choice. Other then those three, I'd make one in the shop before considering any of the others.