The first episode of Fairy Tail isn't bad at all. A decent single episode story arc opens things and introduces three main characters. Only one of these characters comes across as consistently annoying (and that's just a personal issue as I'm certain others will actually enjoy Happy) and the animation isn't always terrible...you'll want to note the emphasis on that last sentence though.
In the first third of the episode, Lucy enters a magic shop and for the next couple of minutes audiences are stuck staring at one of the worst tertiary character designs of the year. Even getting past that, a few moments later Lucy is walking down the road and looks like she drawn while no one was actually looking at what they were doing.
The tone and opening story for Fairy Tail really doesn't do a lot to break the mold of the genre. For a shonen series, you generally expect buildup-setup-big fight scene and you won't be disappointed here. Keeping the tone light hearted, the comedy within the premiere isn't particularly clever or witty but it keeps things moving and fun. Relying mostly on sight gags, occasionally the series will drop a slightly clever character joke and that's what I would hope to see more of in the future.