Mark, I tried it some time ago. But I was never able to accept its concept of floated and completely undockable windows. I found it silly and very unfriendly. I like well organized and dockable workflow. And windows floating here or there are everything else but organized. But maybe it's just me?
My personal favorite was always PaintShopPro. But after version 8 it started to be huge, slow and unstable. I once tried the latest version and even thought there are some nice and useful tools, I still think the version 8 was the last usable PSP version.
If I may suggest you something, try a program, where you can save all the development parameters along with processed image. In the past, I sometime created a very nice picture (either color or B&W). But I was never able to to reproduce it again with the same or similar picture. Simply, I forgot all steps and tools I used on the original image
Now I'm using Silkypix and I'm perfectly happy! After saving the processed image, Silkypix automatically saves the settings file with all used tools and parameters. And next time I open the source file (either DNG or JPEG), Silkypix automatically loads last saved settings for just loaded file. And you can save/load these settings also manually to/from another file! So once the settings are saved, they are not lost and can be used with any other file!
I'm sure, some other RAW/JPEG developers can do this too (for example Lightroom). But I personally think that SilkyPix is currently the best tool for Ricoh DNG files. It's a tool "Made in Japan" and as we all know, GRD/GX100 cameras are highly popular in Japan. Maybe it's just my false impression, but I think the SilkyPix developers take a special care about Ricoh files?