It's not always possible to run both.
If you had to choose: Edwin or Pan.
Depends on rest of the deck and what the banlist looks like.
If I had to choose: I'd go with the gut feeling.
Yes, of course. I mean in general if you /had/ to choose on face value alone.
Edwin but most people would choose Pan
When I play Nightmare I find Timmy much more useful than either, but that may be just my play style. Why not try Timmy?
If you want to choose between Edwin or Pan though, Pan is definitely better imo.