I compared the 1993 Ramcharger and the 1993 Grand Cherokee on the fueleconomy.gov website. For the search criteria, both had the 318 and automatic transmission. The Jeep is rated 1 mpg higher than the ramcharger in town and 2 mpg higher on the highway.

I like the Ramcharger better than the Grand Cherokee. Personal opinion mostly based on the appearance. I think the Ramcharger may be a little wider than the Grand Cherokee. Elbow room is good! The Ramcharger has a separate frame. The Grand Cherokee, especially the limited models, have more luxury features, such as leather seats, etc.