Stew,
I didn't respond earlier because I have a different brand of mortiser than you listed in your poll.
Regardless of which mortiser you get, the degree of sharpness of your bits and chisels will have the greatest effect on your degree of happiness with your mortiser. I found that using two different sharpening tools improved the operation of my mortiser and improved my satisfaction with it. I bought the mortiser sharpening kits from Wood Craft and Rockler.
The Wood Craft sharpener reams or cuts, if you will, a new face on the cutting face of the chisel. The Rockler kit uses diamond encrusted cones to hone that face. I ream them when necessary and touch them up with the diamond hone.
It's important to flatten the outside of the chisel too just like the back of a chisel or plane blade.
Then I also sharpen the cutting edge on the bits.
I can't place enough emphasis on the bits and chisels being sharp.
My initial impression of using my GI mortiser was "so-so" but after sharpening, I truly enjoy using it!
My final choices was the PM you ordered and the GI. I am sure you will be happy with the PM.
Ken
So much to learn, so little time.....