Is there any reason to use RTAI over other option?

I'm considering to install Debian 8 Jessie (stable) using CONFIG_PREEMPT_RT or Xenomai instead of RTAI to use LINUXCNC (2.8.0-pre1). ¿Is there any technical reason to use RTAI over these other options? Thanks.

RTAI typically has lower latency than Xenomai or Preempt-RT
This is usually only important for software step generation.

Note that Linuxcnc does not currently support Xenomai, only RTAI and Preempt-RT
and Preempt RT is only supported in LinuxCNC 2.7 or greater

Preempt-RT can have decent latency (good enough for software step generation)
on _fast_ machines:

freeby.mesanet.com/h97-g3258-preemt-rt.png

and typically runs quite badly on slow machines:

freeby.mesanet.com/atom-330-preempt-rt.png