I recently converted my mill to run under PathPilot, and I like it more than Mach3. However it requires TTS tool holders to run as intended. Since I didn't care to spend the $ to acquire these, I need to stop the program at every tool change so that I can zero Z. At that point I restart the program manually at the tool change line. Other than that, I'm happy with the changeover, and can get faster rapids (now running 120ipm vs 75 previously).