This turnin for texts doesn't give any Cenarion rep, but he sometimes sends you shadow resist tailoring and smithing patterns in the mail. Patterns are fairly cheap on the AH though, so generally better off giving the texts to the Cenarion guy.
Also has a chance to send you the instructions to create the beckoning items to summon specific templars, dukes or lords. Very useful for the tactical quests.
I turned in over 150 encrypted twilight texts over 2 hours ago, and still have nothing in my mail from this Hermit Ortell guy. I have logged out of the game completely, been on alts, and still nothing. It's possible he doesn't send the tailoring or blacksmith plans anymore.
EDIT: After turning in the encrypted twilight texts yesterday and not getting anything for several hours, I was rather surprised to see 12 letters with attachments from Hermit Ortell in my inbox this morning (03/31/12) four of which contained either tailoring or blacksmith plans. So, he does still send stuff after turning in the texts, but it just takes longer to arrive. Must have been because of all that sneaking around to find a mailbox.