I figured it was done, so I closed it. I got an answer from Tormach this morning. They said they settled in 15is^2.

I have more than one machine now and I can see the difference in job time measured in hours on some jobs. I'm really not guessing. I have a copy of Mach 3 installed on my design computer and I routinely run time estimates on on using the Simulate Program Run on the Tool Path screen to see how long a job will take. I have XML files from all of my machines in the directory with it. The PCNC770 looks like a great compromise machine for the average hobbyist and even for some types of small production work, but its not quite right for what I do.

I'll keep an eye on them for the future, but for now its not the right machine for me.

P.S. Closing this thread now too.