Apples and oranges (Score 2, Insightful)

I think that a better questions to ask is whether to choose between .Net and J2EE, since CORBA is st a very small subset of these two technologies. CORBA is a technology used to find objects on a network, which is something that .Net and J2EE also provide, along with more usefull stuff as persistence, transaction,and security-handling

Of course, there are most certainly other frameworks than .Net and J2EE which provide such services as well.