In D2:ED I went with Hermosa, Wesson, Barbatos and Jonelath (didn't like Igor's voice or Allan's personality).
With the skill trainers Hermosa is slightly cheaper raising the level cap for warrior skills, while Kenneth is slightly cheaper with mage sills. The difference is not that great, though, especially since gold is so easy to get once you have the battle tower.
Sentinel Island Servant picks.... - D2:ED topic, but AFAIK things are mostly the same in DKS. The effect for the book Kenneth wants for one of his quests was reduced, but IMO it is still better to use it yourself than complete the quest.
In D2:ED the book gave 5 skill points; in DKS it gives 3.
