[Rails] Does Rails perform better-or-worse on different O.S.? Linux, FreeBSD, OpenBSD, Solaris in particular

[Miles Keaton]

We're at a point where we could choose any O.S. for a soon-to-be
launched Rails app server, and are feeling pretty neutral about it.

The choices are Linux, FreeBSD, OpenBSD, and Solaris.

Since Rails will be running everything, I'm wondering if anyone has
seen significantly better (or worse) performance in any of these O.S.
in Rails in particular?