We operate epic with the charting option and find it very good, we do however brief and fly on paper, we subscribe to Jeppview and have the latest charts up to date.
We use the geographically referenced charts with position overlay for taxying at big airports - it is a great safety help and cheaper that RAAS.
Cockpit space is also a consideration for EFB's
Until somebody invents a touchscreen EFB that is in total A5 size that is light and unobstructive enough to bolt to the column without getting in the way then its paper for me, ideally it would also have a independent source for the P2 side
Recently due to a problem we had cause to consider an enroute divert we simply put all the candidates as waypoints at the end of the flightplan within the FMS, EPIC recognised them and immediately put them in the quicklist for available charts, by examining the charts on the MFD we quickly came up with a plan D E & F within 3 minutes, god knows how long it would have taken wih just paper. Viewable MFD charts repaid their $80,000 purchase price and $4000 subscription that night thats for sure
The writing is on the wall for paper charts, the technology has to mature in much the same way that GPS did - remember the trimble 2101? - maybe in 5 years for new a/c paper will be gone.