Fairy Tail started out as a very promising comic! It threw me through some very exciting arcs, tied me in a knot with it's plot twists, and even brought on small bouts of sadness. I have seen comparisons made to One Piece, and I would agree somewhat to those points. However, after a certain arc, the story starts to drip out of it's bucket.
Given the never ending, hopped up, exciting pace of the story, one would expect the plot to develop at a rapid pace. Hopefully keeping you on your toes every week, squirming uncontrollably for the 7 days in between each instalment. If you've read the FT Wikia, you would realize that this story has some very incredible plot development and some things are just dying to be revealed. The author has let us down.
I would not be surprised if the author has actually died, and they've covertly replaced him with some fraud. I'm dead serious, the story progression for this manga has burnt out like a log. Plot progresses at an un-moderated pace, whipping you around like a wet rag trying to find some bear skin. When it finally makes contact, it hurts... There are times for devastating plot change. One Piece did it well, hell even Naruto did it well, but Fairy Tail did it for the sole purpose of doing it. Seriously, there was absolutely no point in it. It happened, it sucked. Life is going to suck now, oh wait they fixed everything in the space of a single chapter. (Note: The story has been terrible for approx. 100 chapters.)
I can't go into much else without spoiling it, so I'll put it simply:
Avoid this manga. Yes, it is a good story. Yes, it starts out well. But if you wish to save yourself the pain of watching a manga die, please do not read it. All we can hope for is that the story will recover in the future, and move on from it's current pig pen.