Quote - thx croc. i think i'll stay put then. if they changed the runtime stuff then interposer will no doubt break or require an upgrade too. i render in C4D; not sure if that's any better:) 

Its better.

Firefly isn't terrible-- there are some things about it that are actually very good (like the displacement). And I like the node editor. But speed/quality wise there's no comparison with a pro render engine-- C4D has a VRay engine, right? Much faster, much more powerful