Easy - if you have to integrate with MS solutions only or if you have a
green-field project and lots of MS-trained developers and sys-admins -
go to COM+.

On the other hand, EJB's are multi-vendor single-spec and provide better
interoperability with CORBA and mainframe apps (through JCA connectors.)

You can run your app on any major operating system without major changes
(often without changes at all). This could turn to be quite a benefit if
you want to use the Solaris 10's DTrace for debugging and the production
apps run on HP-UX (or win2k for that matter ;-).

Otherwise, if you do bullet-list style feature comparison, both
platforms are roughly equivalent. The major difference is that MS
promotes single and consistent architecture template and the Java camp
have focused on the diversity and natural selection of the frameworks.

Dimitar