Each Instructor has a "feat" and often an "improved feat" to offer you.
The feats add a small bit of experience but more often add an "advantage" be it in combat / resting / game play. You usually have to "visit a site" that opens in the campaign map to "learn" the advantages of the feat.
There are usually pre-requisites for a feat. i.e. Each PC in the party must have at least one rank in Survival skill ; or each PC in the party must have weapon finesse. These are just a couple of examples. The Instructor provides you the details when you speak to them.
Obviously with the "prototype D & D party" (mage/thief/cleric/fighter) you cannot achieve all these party bonuses. You will have to select from a few as it is unlikely your Paladin Favored soul is a weapon finesse build .... just as an off the cuff observation.
The feats are not game changers but do in fact add an edge in playability.
I doubt you can farm the experience point bonus of all the feats but I could be wrong.