Of course I bought both. If you’re interested, I bought the non-Mac App Store version of Coda 2. The only advantage that the MAS version has is iCloud syncing, and even that is restricted (as of now) to Mac-to-Mac Coda syncing.
The Panic version, on the other hand, doesn’t have to fulfill sandboxing requirements, and can be built as Panic wishes in the future. It isn’t susceptible to Apple’s whims.