I initially used gimp with UFraw, but now use gimp with Raw Therapee (it had more features than UFraw and I think it produced better results).
Gimp doesn't force you to use jpegs. If you like UFraw and install the UFRaw plugin for gimp, when you open a RAW file (from within gimp), then gimp will open the file in UFRAW first - this is similar to Photoshop Elements which will open the RAW file in Adobe Camera Raw.
As I use Raw Therapee, I open my RAW files in RT and save the result as TIFF files, then open these TIFF files from gimp.