Wanted one of these for awhile. Could not justify the investment. Simple solution: stop trying to justify it. Did knock off a little expense starting with some Wen bits ($35 10" aluminum oxide wheel, $43 dollar jig set) added to the no-wheel-or-tools included Tormek T8 Custom model. Could keep it in the current configuration for D2, VG10, CP154, and the like. However, for S30V, S110V, M390/CPM20, and 4V I'm getting some CBN wheels from Knife Grinders in Australia. They appear to be the only diamond or CBN wheels designed to run in regular tap water.
Still in the learning curve but the Tormek design does not disappoint. Excellent results. Fun to use.