I run GS/OS 6 on my IIgs mostly just to dump disk images back to floppy so I can boot from them and play the games.

My system is a basic ROM 1 GS + 1MB RAM card (1.25MB total), Apple rev c SCSI card + 120MB HD, 3.5" and 5.25" floppy, Color monitor, joystock. 1.25MB of RAM is enough to run GS/OS with HFS and networking support plus get shrinkit running to duplicate disks.

All in all unless you have 4MB+ RAM and a CPU upgrade GS/OS is just painfully slow to use.