My machine has been great. I find the LNC M5800 controller to be pretty straight forward to use. It rapids faster than I am comfortable with so I usually run it at 50% rapids or less. I don't run large enough batches of parts to track it's repeatability. My parts are always within the tolerances I try to hit. I usually try to work within a .001 in or .02 mm. I rarely miss and if I do it is becasue I wasn't paying attention. It is a better machine than I am a hobby machinist.
About the only issue I have had with the machine was the automatic oiler was mounted a bit too high and it was siphoning out into the coolant tank. Other than that it has been problem free at least for other than the ones the operator creates.
Support for me has been good when I needed it. I have always gotten a response from an engineer when needed. I must admit though that hasn't been needed much. The facebook group is pretty solid and there is plenty of info available there. I haven't had any need for parts replacement at this time so I can't offer an educated opinion on that one.