I love the metal models. That said; on the issue at hand; I'm sure that FW and GW will clear up problems *over time* with Finecast as it's probably still being "perfected." The detail compared to even metal models is quite crisp however and it makes sense from almost any perspective to go that route if that's the case.
The detail is without value if it bends while being painted or is paper-thin and crumbles to the touch. Seriously, go and buy the FW Space Marine character conversion set and tell me with a straight face that the sword in that pack is worth the resin it's made of. I've got that kit twice, one is finecast and the other not, but the sword is garbage in both versions.