The toughest part about both those classes is pet management. You have to be able to quickly move and stop your summon's actions. Best way is to assign hotkeys to the pet's "place" and "steady" commands. Those will let you move your pet and tell it to stop. To reactivate your pet from steady, you will have to use the "guard" command.

Once you have those down however, it is not terribly difficult for either. I'm still trying out summoner, but this is my impression of them so far. Summoners can be bursty, but they're really slow to start. it takes a lot of time to stack on the dots you need to launch your damage combo. It has some benefits but it makes you less remarkable in brief fights with trash mobs.

I think scholar is a very powerful healer. Clever positioning of the fairy lets you place it near the tank and covers blind spots in case they decide to duck behind a corner. The fairy's ai is very simplistic however, as it will heal the person with the lowest hp. This can cause some problems when two people are at low hp and you're trying to heal the priority target. You have to learn to manipulate that ai to help heal the target you want and keep the situation favorable for you.