Hi athouston,
you are right, that freescale forces its iMX6 chips and has a quite pretty support for them. Additionally
there is 'real silicon' available for all variants: single core, dual core light, dual core and quad core. I
mention this, because it was not always fact in the past - freescale was a master of announcing, but
not of providing silicon (e. g. the 'Kinetis' line of CPUs).
I think selecting a specific CPU or board depends on your needs also. If you want systems, that have to be available
for more than let's say two or three years, then Allwinners/Rockchips might be o. K. If your need is to have them
significantly available longer, then the freescale chips are more interesting. The iMX6 CPUs are part of freescale's
'Longevity' program, that means they will be available for ten maybe 15 years.
Did you take a look at the 'Wandboard' which is a low cost iMX6-board? You can get it with single core,
dual core light or quad core CPUs. There have a forum and IIRC questions about TC support have been asked.
best regards xyz-worx