I am also interested in this.
My personal story: three things made me commit to Slice (I already have a mini-itx silent with Kodi). Raspberry PI multiple operating systems, Spdif/Optical output and ambi-light integration.
When I committed to the project it was because the ambilight target had just been achieved. Today, the system is ok but I cannot use the optical output because it does not work yet, the multiple OS support is pending and ambilight probably canceled forever. I hope the new compute module will bring a new life to some of this features. If not, then you are better off buying OSMC or a FireTV memory stick. Today I read that the FireTV does everything that my Slide does for 1/3 of the cost (only exception the HD that I do not use) and it also supports Netflix and Amazon Video. OSMC has better support and active forums. It may be that the future support for SliceOS is to run OSMC.tv instead of SlideOS once CM2 is out.
As Gordon said before the software development is costly and the number of sold Slides probably does not help with this. Not a rant, just how I see it right now, I hope I am wrong. I lilke the Slide right now I have the feeling that its future is fading slowly.