Ben,
Looks like you went with the AP12000X. Support has been great with mine, Arc Max . Two things you may find out.
1) Make sure your post processor is the latest REV. IIRC it needs to be 24 6.1.50. If not the hub will dive or fade during cuts. Mine was fine for about 4 weeks and then it started acting up.
2) The tool parameters are not correct for a majority in SheetCam. Preset volts, feedrates and delays are not set properly. I have the latest and greatest parameter sheets for the Hypertherm 65-85-105. Email me and I'll send them to you if you don't have them or your tool sets are incorrect. It's pretty easy to tell. Makes a world of difference on the cut quality.
Jason