I usually only dabble in it for novelty purposes, including Super Number Munchers and Oregano Trail.
I'm currently running it on both my intel imac, my ibook, and in windows with sheepshaver. It'll crash sometimes while web browsing, but that's about it.
Ironically, I actually had to use it today! I have a virtual Windows 3.11 machine in Parallels with no CD drivers. I downloaded a TCP/IP stack for 3.11 from microsoft.com, and transferred the files from OS X into OS 9 via sheepshaver's UNIX mount of my intel imac's home directory. I then used OS 9 to make a DOS 1.44 mb floppy disk image of the TCP/IP stack using OS 9's disk copy utility. (I can't seem to make 1.44 mb DOS floppies with Disk Utility in OS X). I then put that 1.44 mb disk image back onto OS X, changed the file to a parallels .fdd floppy image, and loaded it into the Windows 3.11 virtual machine.
Since I'm working on getting internet access in 3.11 under parallels, this is currently the only way I can get files into the 3.11 virtual machine. Hooray for OS 9!
Like I said, novelty purposes only...