We just purchased a new Solera 24R and yes the Sprinter gets 15mpg. I did not purchase this for fuel saving as I can never live long enough and travel far enought to see any cost saving. I wanted a smaller and easily manuverable unit and this fits our needs. Not easy going from 30 foot fiver and not missing the storage space. We will manage as I believe we always took more than needed as we had the space. I was needing to replace my truck and wanted a new RV so we made this change but would not change for fuel savings only.
Have Fun
BadBob