No insides for this guy, not even on Crystal. Seaborne doesn't have inside cabins so I don't have to worry about that one.
It all boils down to bang for the buck. I have never sailed either line so I can't say I won't but Crystal is luxury but, from my understanding, it is a more traditional cruise experience with traditional dining and more standard itineraries.
Seaborne on the other hand has smaller ships that will get into ports that larger ships can't. That, plus the high end service would make me "think" about dropping the $$$$ for it.