I've read this before.
As far as I can remember he is using the same drawing technique that Oda does.
That's why the characters look like they've jumped out of One Piece.
But since there are not unlimited ways/styles to draw characters, it's not surprising that they look alike.
The story and the worlds it's playing in are different, so it's not just a rip-off.
I think Fairy Tail is a very good manga and I hope it goes on for a long time.
The thing about Natsu-Ruffy is, that it's not just Ruffy.
Goku, Naruto, Ruffy, Natsu. They are all pretty much the same person.
They are naive, good hearted, have a stron will, high stamina and they eat a lot.....
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"