I, too, export a neutral TIF from SPP. However, the performance of SPP, while never good, is abysmal on my notebook and virtually impossible to use while in the field.
So, I am looking for something else to do light processing on X3F files.
I do understand, Alan. That is why I'm sticking with my SD9 and SD10 and SPP 3.5. I've occasionally downloaded Merrill X3F's onto my oldish desktop computer and opened them with SPP 5.5.3 and, to be frank, I don't see how anyone puts up with it. Especially that sad trick of editing a 'smaller' version unless you push this button and then go and make coffee while it loads. Rant over.
RawDigger can open Merrills and export an RGB 8bit TIFF of sorts pretty quick, but I doubt that's the kind of workflow you're looking for. FastStone Viewer can extract the full-size JPEG but I'm sure you don't want to do that either . .
. . . not much help am I? How about buying a Mac and using Iridient? [edit, someone just mentioned that]