Rectangular st handle is my favorite. I know bty jun mizutani, Timo boll series have rectangular st handles, primorac carbon as well. What other blades have similar st handle?
The Freitas alc has a round st blade that I am not that fond of.Some other Butterfly blades come to mind, like the Maze and the Schlager.
I recently bought a Sanwei 75.1 and that has a squarish straight handle. I'd highly recommend it for the price