I have always written the Rx on a script pad. Now, I like the idea of eRx because it records the Rx in the chart. I don't like my staff calling in Rx because they inevitable "forget" to document that they called it in and I have no record of it. My most common Rx is by far and away, narcotics. I like good documentation of those. I like the computer in that it documents the date it was prescribed and the exact medication so I can look it up at any time, any place.
During clinic, I write on the superbill because that's all I have in the room with me and the patient. Works for me.