I don't think too many people will contend that Ttokkyo Testanon 250 is as good as Organon's Sust redijects, however, it cost nearly 3x what the Ttokkyo costs, so quality is not the only factor.
I have used them both, and find the results similar, but the pain was much worse with the Ttokkyo. Personally, I would be more inclined to go with AraTest 2500, or a single ester Test over those 2.