Hal2Arduino

Has anyone used Hal2Arudio as a PIECE of their system for a SLOW I/O expander? Please share good and bad experiences!

I am thinking about using one. Why? I want more SLOW I/O for estop status, coolant pump control, oiler status on/off, a jog wheel, spindle on/off, cheap.

On what?
I am retrofitting a Shizuoka AN-S mill with LinuxCNC (yes, Still! I took the summer off, and if I wasn't shopping for a car for my wife on the computer, I shouldn't get caught using one Anyway...

I had a little trouble getting it going and updated some files for hal2arduino and a poor quality quality how-to. They are on my project page where you can read about the mill.
sites.google.com/site/yeltrow/shizuoka-a...-linuxcnc-conversion

What keeps me awake at night? I think it uses change of state to determine when to send a packet -- I think I want to add a timer and have linuxcnc detect loss of connectivity for more than 10ms. It might be good to include a checksum in the packet. I think one also has to keep "failsafe" wiring practices in the forefront of their mind using something like this.