which would be the best raw processor for the XE-1?

Oloneo PhotoEngine is very good tonemapping and image stacking software for single image DR expansion and multiple image HDR. OPE uses a DCRAW based algorithm which has difficulty with some X-Trans RAF files.

But, for other than opening X Trans files, OPE is an excellent software. For example, save an image in RFC-EX (Silkypix) as a single or multiple image JPEG or TIFF with various EV values and use OPE tonemap the single or multiple images stack to extend the Dynamic Range.

Here's an example of a single JPEG that's too dark:

==> Single Image HDR... 

and single image saved with various EVs: (Check the Sets with C1 and SP5, and C1 vs. SP5; view full screen as slide show and use arrow keys to toggle between images):

==> Single Image with Multiple EVs