Sent it off to Sheaffer with a request to either dry out the nib or replace it with a F.
Now, with a F, it is scratchy and excessively dry. Also, the feed appears misaligned with the nib.
So, I guess it goes back, with a request to restore the M nib, and hope that the one I get will be a little drier.
Otherwise, anyone want to trade for a really pretty pen that I'm, at this point, not that happy with?