I installed a microarc on my 1100 and milled a part out of 1.5" 12L14 steel. Had problems with the part pulling out of the 3 jaw chuck, but by adjusting cut depth, and stepover I was able to make it work well.
Rotary toolpath really did not help me for this part, and it needs to have multiple depth of cut added.
Overall I plan to use the microarc for work with brass and some steel, all of which is below 1" in diameter and can be held in a collet. I think it will work very well for me.