Besides the backlash on Z you also have table flatness. For a small area the flatness can be pretty good but overall my table varies across X about 0.003" & Y about 0.002". This is a little more that the G2 inspection report says it should be and a lot more than the QC department measured on my report.
Since my manual mill" (10" X 50") is flatter than I can measured (less than 0.0002") I've been thinking about pulling my table off and fly-cutting it.
Most of the time I can live with the Tormach slop, or account for it, but in the back of my mind I'm always wishing for tighter machine but then I have to remind myself about the price point.
You can download the
Certificate of Inspection from Tormach to get an idea of what to expect. I would look closely at the max allowed values because that's likely where most machine are - they don't tend to be better IMHO.