Game runes fine, in general... with the following problems: Game is laggy and slow, animations take a long time to process. Bottom of screen (fullscreen mode) is cut off, cannot see conditions, HP, and other parts of the bottom of the UI. Regarding the upgrade to Mavericks: I have a 2008 MacBook Pro w/ 2.4 GHz Intel Core 2 Duo, 4 GB Ram, and an Nvidia GeForce graphics card... Upgrading was relatively easy (if time consuming), and only cost me a total of 20 dollars US. If you rely on legacy software, do NOT upgrade to Mavericks - you won't be able to run it any more, not even with Rosetta (because it no longer exists). Upgrading to newest version of Java (7.1 I believe) is no problem for Pox, but is a problem for some other Java-reliant programs... so be careful there too - you can downgrade to Java 6 without much trouble if you discover it was a bad idea to upgrade.
When you say "Game is laggy and slow, animations take a long time to process." is it always like this or only becomes this way after the client has been open for a while?