You'll find that Ragamuffins boast a lot of permitted colour variations which includes a lot of white but excludes pointed colours. The Ragdoll, however, is only pointed which basically means their bodies are lighter in colour than their faces, their legs, tails and ears. With this said, Ragdoll can also have paws and some white up their legs.
According to the Cat Fancier's Association, both breeds boast coats which are described as being medium long and both the Ragdoll and Ragamuffin have plumed tails. The one distinction the CFA makes between the two breed's coats is the fact that a Ragamuffin's does not easily become matted.