I think if you avoid letting the blade get super dull, that you'll be okay with the Sharpmaker. Lots of folks report the ability to keep their 440V blades fine with the Sharpmaker.
If you have to move some steel, that would likely be a different deal altogether. I'd think in terms of a diamond stone, maybe one of the pocket variety.
According to Sal Glesser, diamond coated rods will be available in the fall. They had a tough time finding a method of adhering the diamonds to the rod that Sal would approve. But, guess they did. Hopefully, one will be able to buy just the rods and add them to the 204.