Admittedly, I have searched Leopard vs. Tiger 10.4, and find nothing new in Leopard (as for my uses) that justifies the cost in $ or hardrive for Leopard. I'll check "Snow" Leopard someday.

Previously, with Tiger I used Schreiben for a while. Speaking of ease and simplicity for writing legal documents and for a lawyer, for writing simple letters, for all the important, frequent, and basic uses, I am more than satisfied with an alternative called "Bean" ( named after coffee bean and those of us who work late at night and rely on a cup of java). Bean is simple pleasure to use and gives no problems.

If Schreiben is really that better, I would think the author would include the few adaptations that would enable it for use on Tiger.
Before passing judgment on any simple processor, you owe it to yourself to download and try Bean.