I use him to get my party back to New Sorpigal after they've visited the Shrine of the Gods. I also use him to take my party to all the places that can be visited via Town Portal before I fire him, especially Free Haven and Silver Cove. That way, I don't have to fight my way right through Bootleg Bay in order to get to Free Haven - I can just take the coach from New Sorpigal. I too use this to pick up the horseshoes from all the stables early in the game 
.But I agree with the Scholar/Instructor NPC combo. The scholar gives instant ID Item to all characters (no swapping around items in backpacks to ID them!), and nominally gives an extra 5% XP bonus. (That's broken in the v1.0 game; I don't know if any of the patches mend it.) This means that you don't need to waste valuable skill points getting one of your own characters up to mastery in ID Item. The instructor gives a 15% XP bonus, so you go up levels faster and get more skill points to allocate.
I've never used a master healer. You can only use them once a day, and they take 50% of all the gold you find. IMHO, that's just not value for money.
