I didn't use Ninjatracker but I'd imagine the low rastertime usage makes it to lacks functions ect. It's already apparent in Goat Tracker.
On C64 one would do better with SDI (Tjelta/Galefoss), JCH (Huss and updates by ppl like Glover or Dane ), SID Factory (Laxity) or X-SID (Jeff).
Use 1541ultimate or smth similar for load/save-stress-free experience 
Also, as 4mat pointed out corecctly, use emulator (try Vice, very good, or Hoxs for 8580) before actually falling into purchasing of real hardware. Also, one do not have to do that - emulator still will do good with HardSID etc. though it sill be siginficantly cheaper to buy C64+1541-II+floppies+Action Replay
Last edited by booker (Dec 22, 2011 4:14 pm)