As I understand it, your *nix solution will be leaner and more stable. I have a Glassfish cluster running on Fedora 7 servers, which has been quite stable and reliable. My caveat to using fedora, however, is that Glassfish requires Sun's Java, which must be installed on Fedora along side the default GNU Java in such a way as to prevent automatic updates from changing the default Java or replacing your Sun Java. That was a bit tricky to figure out, but I've detailed the process at
http://blog.augmentedfragments.com/2007/11/project-part-1-fedora-sun-java.html if you decide to go that route.
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