Unless you need low power or have very little space availabe, a PC with a real disk drive
is pretty much better in every way than the ARM platform for LinuxCNC
With a few exceptions, the ARM platforms suffer from cellphone-itus:
#1. Short product lifetime
#2. Bad documentation
#3. Kernel bugs that are never fixed until the product is obsolete
#4. Every new SOC is different so you start over at #1 every couple of years
#5. Often dismal graphics performance compared to X86
Basically the consumer embedded ARM chips are not a "platform"
in the same way a x86 PC is a platform
If you really want to use ARM, I would suggest Machinekit/Beaglebone
The Beaglebone uses an industrial SOC instead of a consumer tablet SOC
and has a couple built in real time processors(PRUs) that can do things like high
speed step generation and encoder counting so the beaglebone does not need a FPGA
for these capabilities.
