The fantom is a goddamn Rompler. I.e, if you wanna manipulate some vocals or use your own sounds, fugehddaboutit.
The Tritons preset samples are weak and the sampler isn't very cool.
The motif is far more powerfull than any of the mentioned. Up to 64 mb ram, the best hardware sequencer out there and expansion slots for FM and AWM synthesis.
It's basically a smack arse piece and the preset sounds are way better than those on both the triton and the fantom.. (imo)