I tend to agree with the thoughts regarding, that more than the designs, it's the pilot that really matters. Now, having said that, A good pilot usually does even better with a good modern design. A few thoughts on available kits.
Brodak apparently is the last major kit producer in the U.S. and there're not too many modern designs in their lineup. The Legacy, Allen BrickHaus's almost 25-year-old design, is still a solid performer today. If built, straight and true, with proper incidences, power, and reasonable weight, it can perform. It may be best suited for Beginner through Advanced, although in the right hands can make a good showing in Expert.
The above caveats, "built, straight and true, with proper incidences, power, and reasonable weight", and "in the right hands can make a good showing in Expert". Apply to every design out there but does show the relationship that exist between the design, building, alignments, weight, power, and the skilled pilot.
A very low time pilot, beginning in our sport can almost start out with anything. As more experience accrues, this pilot can be held back from making decent timely progress, by his equipment. By stepping up to a better design this pilot can continue on in development faster, and more accurately, as his "Mount" of choice has better capabilities.
RSM kitted Gordan Delany's Pathfinder L.E. a final full-blown, full bodied, last in the series version, of the successful Pathfinder Profile. The Profile is a very decent competitor in its class, as well as some of the PAMPA skill Classes. The L.E. is just starting to make its appearance at comps. The two Prototypes, one of which I own and fly, is a pretty good performer and should begin to show its capabilities as more are built and flown in competition.
Brodak markets an interesting small version of the PF L.E. named "Little Elle". It's a .15-.25 sized adaptation of Gordan's larger L.E. The fuselage was slimmed down as it was not intended for a pipe and didn't need the extra depth in the lower fuselage to hide one. reports are that it is a decent small stunt design that flies pretty darned good.
There are others, but most are no longer being produced. Kaz Minato's "Blue Max" comes readily to mind. With the shut-down of RSM, there are few manufacturers of new, modern stunt kits. Additionally, With the loss of almost all the U.S. model aircraft magazines, we are seeing the loss of plans and articles for new modern stunt designs here at home. If this keeps up, it may become hard to get the plans and information about new designs.
I believe we are fast approaching the point where we will need to become "Scratch-Builders" as it may soon become almost impossible to buy a kit for a modern stunter except possibly from a collector, or estate sale.