I do miss some features like the ability to map out function keys. EG: Programming F1 (easily) to open your web browser. I miss that in OS X. I've found a third party that does it, but it's not as easy to do. AppleWorks always seems to run better on my iMac G3 than my G5.
I came in during Panther, and the Geek Squad restored my system and installed 10.1 and 10.1 only on it (no OS9), and I wished I had OS 9. I got my G5 about two years ago (less than a year after I switched), and I knew enough about macs by then and had no use for the files on it anymore that I restored it to 9.1 and 10.0. It's been a good general web browsing computer that's been placed in various places, but I finally got my mom to switch, so I had to reinstall Panther again after restoring it between 9, 10.0, and 10.1 several times. However, any time I use it now, I reboot into OS 9. 🙂
If only I could find a web browser for it that's significatly faster and less clunky than MIE 5.2.