Well, I'm running a campaign using the GURPS 4th ed. ruleset, in Western Shem currently, and my players seem to love it. Started in February, still going.
We have an Argossean ex-bandit (was a shemite slave from birth, escaped, and became a survivor before joining a band), a real miser, a young Asgardian warrior, bent on finding glory or death, and two Shemite mercenaries (an ex herborist - turned - criminal, and an ex- farmboy - turned - criminal). All are more or less mercenaries to be able to move quite freely, and be employed to be authorized to wear their armor (you cannot wear metal armor in some places in my world if you don't have a "sponsor". Gards don't want unmanageable killers in full armor).
Currently, we play in Western Shem, but actually didn't travel a lot. Started running from a raiding Kothian force, fleed into a haunted city, which have been properly looted, freed from its ghosts and evil priestess / demon worshipper, and lost themselves in problems at the closest little town they could find. Soon, however, they'll hit the road again. Desires have been made clear of getting valuable armors and weapons, pillageing ancient ruins and gaining glory by blood.
And the books are wholly vague on Shem. Population is too low, no good map exist, and no comprehensive and usable city list, so ... I'm trying to "build" my own Shem, using data on its climates, geography, and other pieces of information, to make a more precise and correct evaluation of population potential, where the city-states are, and other sutff, the more "realistically" that I can manage... Hard work.