Alright so Eden's Zero is a series that gets a lot of unfortunate hate, anyone who has actually read the Manga will realize its much more than just a rip off. Character designs are practically reused, certain characters dating back to Rave Master appear here, and that's totally acceptable, an artist should be allowed to use their own designs however they want.
Eden's Zero has a great setup saga, spanning nearly 80 chapters, and while this is a huge let down for some, it seems people have come to expect perfection crammed into a minuscule amount of chapters or episodes, which simply isn't possible. Everything, and I mean everything you have seen or read from the beginning of the series has a purpose, and it keeps proving it again and again the further you read. Eden's Zero does not waste its potential, and delivers in moments you least expect it. The pacing of the story is comparable to One Piece, but not as long of course, I think its a great manga to pick up if you don't want to read the longer ones out there!
The art for this manga is fantastic, it is definitely some of Mashima's best work out there, and although it could be better in places, its still extremely impressive.
The characters all have pretty interesting backstories, and they tie in pretty heavily to the plot of the overall series, while I do wish there was more going on with that, I'm sure it will come with time, after all the series is about uncovering a grand mystery.
Overall, i am extremely satisfied with this series, and I believe going through the slow and steady build up introductory arcs was worth the time. Before giving into the criticisms about designs, give it a shot and see if you like the story, if you don't that's completely fine!