Well, it is good. Excellent, even. I'm sure you'll love it. But yeah, if, somehow, you don't like it by the time you've completed the arlong arc which gets wrapped up by 40-50 episodes, I don't think you should continue. Watching till that arc will give you a pretty good idea of how One Piece works. So yeah, if you don't like it by then, stop. No need to torture yourself for 500+ more episodes. :p Although I have to say if you like the arc and what you saw before it, you should know that it is only the beginning of how good the show can get. The show doesn't deteriorate in quality after an 'x' amount of episodes, really. There are plenty of epic arcs later on in the show. ;D
But yeah, don't look forward to the OPs too much - they tend to be a lot less impressive compared to FT or even Bleach's. The initial ones aren't all that good, imo. Maybe the OPs after the 10th will be liked by you. 13, 14 and 15 have been pretty amazing. 13 is pretty much the best opening I've ever seen for any anime. Ever. Oh, and One Piece hasn't had that many EDs. I mean, most episodes just end with a "TO BE CONTINUED" thing. :p ALSO there are no powerlevels aka DBZ. Weak people can defeat strong characters if they use strategy. That's another thing I like! ;D
...you just made me want to watch the show. I think I will give it a chance, given how good you made it out to be ;_; The art style's definitely not a major issue, since I didn't like Fairy Tail's art before I actually watched it, either. I REALLY WANNA SEE THE JAPANESE OPENINGS/ENDINGS FOR OP TOO
Btw, I didn't reply to your previous VM because I was planning to write a tl;dr on WHY One Piece is pretty much the best anime I've ever watched. But I guess I'll just write whatever I can right now with the limited time I have before I go offline - One Piece is all about the plot. It is, pretty much, a plot-centered manga with some epic and really clever fights in it. It'll leave you laughing on floor whenever the protagonists do something silly but it'll also make you shed a tear at the loss of lives of the characters that inhabit its rich and vast world. Screw characters, have you ever cried at the loss of the so called 'life' of an inanimate object? No? Well, you'll cry while watching One Piece. I remember crying while watching anime at only one other instance - when Madara tells the truth about Itachi to Sasuke. But yeah, won't go off-topic. :p One Piece is good because you feel what the characters feel - their anger, their sorrow, their happiness and even their hatred. Also, one thing that separates One Piece from other manga like Bleach, Naruto and Fairy Tail is its dynamic world - nothing is static. The mangaka has made sure that the world is affected not only by the actions of the protagonists but pretty much every character that inhabits its world. Also, almost every side character gets its due share of character depth. They aren't ignored just because they are side characters.
But yeah, I've rambled on for enough, I guess. The only thing that keeps people from watching this show is its slightly irksome art style, which gets better as you watch, and the slow pacing of the initial episodes. It'll seem a little slow for the first 30 episodes or so but you probably won't be able to stop yourself from watching by the time you've reached, say, fortieth episode or something. Every single irl friend who was recommended One Piece by me got hooked after watching and giving it a chance. Ignore the art style for a bit and I'm sure you'll enjoy it. Like I said, it gets better - maybe because One Piece is more of an acquired taste. I mean, you'll start to love it while you watch more and more of it. ;] Here's a pic which shows how the art evolved, btw.