OK, thanks.
Perry's message about Java for client development is consistent with some things that I've read, though again I've never really used Java. I've also spoken to someone "in the know" who said that Java runs more slowly than C#/.NET.
I'm only personally aware of one major Fox application that's being ported to Java, and that's largely because the organization has a number of in-house Java developers. (I'm sure there are many out there).
It's easy for me to say "do it all in C#/.NET", because that's my bread and butter (and bacon!), and you'll find a lot of good information on this forum. (Heck, just read through Bonnie and Cathi Gero's posts and you'll find the equivalent of a .NET encyclopedia). There are many factors to consider - I think one is the existing knowledge base in reconstructing your type of application in either tool (I'm not talking so much about specific functionality, but more general architecture).
Kevin