I use recipe known for my toon and its never worked in my auction house (color wise) bc I use baud auction. So what I've been doing in the Auction House is clicking the usable item option which is only good for the toon I'm on. Anything recipes or even pets I've already learned don't come up. When it comes to vendors the addon works just fine for me.
But for alts I would suggest Altoholic. When your with a vendor you do have to roll over the tooltip but it will tell you who has learned it and who can learn it. It will also tell you if you have it banked in a guild or the alt's, any of the alts. I prefer this WAY over RecipeBook and if you haven't seen it already it's here:
http://www.wowinterface.com/download...Altoholic.html .
It doesn't feel that tough learning wise, but you do have to go through all your characters, Mailboxes, banks, guild bags, skills, etc. But it's totally worth it.