NT Service/COM

I'm beginning an app that screams C/S: a server .exe that will constantly
run scanning directories for incoming files and processing the data that
appears there -- plus a client .exes used by end-users to maintain and
monitor the server .exe.

What are the pros and cons of making the server .exe a COM server (run on an
NT Server) and or an NT Service? Any pointers to articles/books/web sites
would be a welcome reply.