I think that Linux's main downfall is the sheer number of versions. Because it's open source, anyone can develop an O.S. and although it has been beneficial long term (i.e. many hands make light work), it has resulted in a bottomless pit of choices. The Linux Mint project has done a lot to address this issue (and done it very well), but newbies may not discover it and give up because they tried some other flavour of Linux. It's a shame really.

I'm not massively into LinuxCNC yet but understand there are loads of custom screens available. How easy they are to install and/or use is something I've not investigated yet...