I have experienced OSX's "swappiness", having gone as far as disabling dynamic paging in an attempt to avoid it. Upgrading memory was the only real solution. A little bit of research would reveal a lot of other people have run into the same problem, you aren't alone at all in that.

I split my time between OSX/Linux and it's pretty obvious to me that Linux is vastly superior in terms of performance, in a wide-range of scenarios. I prefer to use Linux on older and/or memory-constrained systems.