One additional question, does it usually install without causing any problems?
I have installed Leopard on seven machines (three intel and four PPC), and all worked fine. That's not to say others didn't have issues, but for me, they all upgraded just fine.
The biggest issue for me was that I lost Photoshop 7 (it won't launch), and had to upgrade to CS3. Office V.X was also a little shaky, but it worked. I have since upgraded to Office 2008, but that is another story altogether...
I think it really comes down to the benefits (latest version, new features, etc), and the negatives (lost some compatibility, takes more memory in some cases).
I think it could easily go either way. If you like the features and you aren't losing anything you can't live without compatibility wise, then I say go for it.
For me, things like Time Machine, and Remote Screen sharing through iChat were well worth it. Having to spend $199 on the Photoshop upgrade was the only "gotcha" that I ran into.