Hi
I've kept both Goliath and Vittatus ATF's. Without doubt, Goliaths are much harder to wean onto non live (I never had any problems with Vittatus taking non live). I currently have a Goliath (@5") eating flake and Hikari cichlid gold pellets.
You have to be brave and refuse to feed live for a while (although I did feed live to start as the Goliath was quite skinny @ 4" which is fairly typical from what I've seen).
One tip I would give you is to slightly pre soak any pellets you offer. My Goliath would try them then spit them out if they weren't slighly softend.
For the record, I paid £130 for my Goliath. Although the best I've paid was £70, and that was a perfect Goliath that I lost in Febuary due to a power cut.