I've used eXceed for windows and MacX for the power mac for GCG. I
much prefer eXceed. I have regularly used eXceed to access GCG
software and it works fine.
If you are running OS2 warp, rather than microsoft windows you might
also consider the port of Xfree that'll allow you to access Xwindows
from your PC. Ports might also be available for other non-UNIX
platforms as well?
Simon T