I've never used C4D so I can't give a fair comparison. As far as chatter from the internets people do like MoGraph a lot in C4D but many switched to Modo because they feel that C4D's renderer is subpar and that it's tools are antiquated and it costs too much.
I can't verify any of the above its just what I've observed others saying.
I would suggest maybe asking over on the forums here: http://community.thefoundry.co.uk/discussion/
There are a lot of knowledgable people there (including switchers and people who use both softwares) that could give you a lot better specifics than I can.
I will say Modo's price is what drove me to choose Modo over C4D.
Ok thanks for the feedback.