I don't know how far the trial goes up to, so I'll give you the whole of ARR. What's actually -fun- in ARR?
The trial is basically a way to get an impression of the systems that the game uses, all the little features, all the little extras. Fiddling around to see if you like the way quests are structured, the way crafting is done, so-on. But the game is fucking boring for almost the entirety of ARR, the dungeons are simple, and the classes are basic. You'll never be in danger out in the world, the story is completely unengaging, and your biggest threat in groups will be the retards you might get lumped with.
Maybe it's true of most MMO trials that your impression from the trial alone will be that the game is boring horseshit, but I feel the need to impress that it gets dramatically better in this one at 50. Whereas in retail WoW, it's that same flavor of being bored out of your fucking mind until you reach the veeeeeery tip-top 1% of the content.