Personally, I think the inside guide wheels are an inherently safer design because the track wraps around the train...so if a wheel carrier is lost, the train won't derail.
Mechanically, the action of inside wheel sets and outside wheel sets should be identical, albeit reversed.
Structurally, if you are Arrow Dynamics and building track ties out of square tube, it is mechanically simpler to build the track for outside guide wheels. If you are Chance-Morgan and building track ties out of solid plate steel, it doesn't make any difference, except that the track ties are a little narrower if the guide wheels are on the outside.
Chance-Morgan, probably because of its Arrow roots, generally puts the guide wheels inside...but put them outside for Steel Dragon 2000. I suspect this may be because the guide wheels are very large. Assuming that like the road wheels, the guide wheels are 18" in diameter, putting the guide wheels inboard would take up 36" of the real estate beneath the car, where the track is typically a 48" gauge...that doesn't leave much space for the chain clutches, safety dogs, and brake calipers.
--Dave Althoff, Jr.