Great feedback - thanks. My motives for querying this are really based on point (2) - I don't want unneccessary business entity proxies being duplicated in the WS consumer/client; I actually have a leaning towards binary serilisation and its great to hear that it addresses all concerns.

I'm interested in why you serialised as binary and not XML - was it just a matter of personal choice ? I have similar issues to solve - did this approach work OK for collections as well ?