I do 2, sometimes 3 passes at the end of the week, skating 3 days a week, 5-6 hours total. My edges are still fairly good at the end of the week so I rarely need to do that third pass. Ring life has been really good so far. I suspect I'll get somewhere close to a year from a single ring.
I had skated on the Sparx product before buying the machine so I was fairly confident in the results. The area that made me nervous, was me, the operator. I always say the machines biggest drawback is the sack of meat operating it.