My first Benz was a Micro Glider back in the 90's. Superb cartridge. After that came a Benz Ruby H. All the same great Benz qualities, only in much bigger doses. The same only better as they say. Really like that sound and really happy, nothing to fault at all, just wanted more and Koetsu seemed the logical next step. Because no way I am trying a lot of the usually recommended contenders, not when already knowing what I like. Sure enough, Koetsu Black Goldline isn't really any different than the Benz's, just a whole lot more of all they do right.
So the answer is yes there definitely is even more out there to be had. Do NOT buy another! Because if you break it soon, well then you do. But if you don't- and if you are careful you never will - then in a few to several years as technology advances there will be even better choices and you will be able to have everything you have now only better for the same or maybe even less. Which of course means if you're willing to spend more then you will be amazed all over again just how much better things can get.
Its not a challenge at all. Simply move up the Benz line to the next one you can afford, paying attention mostly to output. Or if you get to the point you can afford it then move to the cheapest Koetsu you can afford, again paying attention only to output.
But that's a long ways off. All this same stuff applies equally if not more so to the phono stage.....