Fairy Tail. It's very similar to One Piece, with "nakama" and some of the character designs looking quite similar (in fact, one could say some designs are plagiarised *cough*Gildartz*cough*) to One Piece and therefore is often compared to it. However, it's nowhere near as good as One Piece; don't get me wrong, it's a somewhat okay series, but it is let down by its story.
The art in this manga is good with excessive amounts of fanservice which I am not personally too fond of but I'm sure it'll appeal to a lot of its target audience (presumably heterosexual males). Still, it ranks only as "good" and is by no means exceptional.
The story is where this manga really fails. Fairy Tail has never had much of an engaging plot, but that's understandable, considering it is mainstream battle shounen. However, something that really annoys me is the use of deus ex machina in order for the characters to escape difficult situations as opposed to more inventive solutions. For example, in one of the recent arcs the big bad was defeated through "the power of friendship", which is a concept which might have some appeal to five year-olds, but unfortunately I'm not five. There are plenty more examples of deus ex machina in this series but I don't want to spoil anymore of it.
The characters are typical mainstream shounen characters. I don't have any real complaints except for Natsu, the main character. His character has received zero development over the course of the 200+ chapters that FT has ran for so far. Despite him apparently learning an important life lesson about how one cannot always win during a battle with someone who far outclasses him, a few chapters later he seems to have forgotten and is back to his old, egoistical self, jumping in, thinking he can protect everything and completely ignoring the orders of his master. If this was any other manga, there'd be dire consequences. Unfortunately in Fairy Tail Natsu always wins and it is always he who defeats the enemies through THE POWER OF FRIENDSHIP- yeah no.
Overall, Fairy Tail is enjoyable, but only if you don't take it seriously at all, pay no attention to the plot and just look at the pictures and watch the fight and comedy scenes. Even then, the fights are wholly unsatisfying because of how they end (again, with Natsu always winning through THE POWER OF FRIENDSHIP or deus ex machina of another kind). In all honesty, I'd recommend steering clear of this series entirely or just reading it for the aforementioned scenes.