I have found that I get more xp when I do the events where I can tag many different mobs while completing the event. In fact the green hills event has proven to be the best for xp. Other than Scalding Mornbrew which is the worst, but may be just worse than kissing frogs. I’ve found the boss events to take too long only to give out a small amount of xp for the kill and the same amount for defeating the event. On a side note, I’ve seen a discrepancy in sometimes not getting the xp for completing the events. Also, the main Bos’s quest itself sometimes just disappears without being able to turn in or to reobtain.