Mostly the place. It's got a place like a Bleach filler. Had it happen before Loguetown, it would have been just another filler arc.
Can someone expand on this 'cause I have no idea what m00n means by this. The only bad thing about the Apis arc for me was that Zoro cuts steel, messing up the event in the Alabasta arc, and that the amount of ships in the armada that they go against at the end makes some of the later canon ship battles seem lighter by comparison. I guess also, looking back, the bad guys didn't feel that threatening. The fat guy didn't really do anything and Eric was more of a nuisance than anything. Apis herself felt like a canon character and the overall idea of her dream and of the dragons made sense.
The G8 arc is good but it's almost all down to Jonathan. The idea of them being trapped in a marine base and just wandering around casually, almost as if they live there, felt incredibly fillerish to me. Then, after it's milked that for all it's worth, the marines suddenly get very proficient at chasing after them. It also got to the point where I thought "OK, I get it. Now can they escape?" but it just dragged on and on without really adding anything new. The very definition of filler. Take away Jonathan and you have something underwhelming and overlong.
It was clever in the sense that as cool as Jonathan was, he really was nothing but a device to milk the filler as much as they liked. When it turned out he'd got their gold and they had to go back I pretty much grinned and facepalmed at the same time. How "Just As Planned!" but also how barefaced and obvious as a filler-extension ploy can you get?
I have to say, the filler that most reminded me of other shounen's filler was the ice island filler (not sure what it's proper name is) when you have that ice skating couple and the hockey guy. Sure, the characters were zany and One Piece-esque but the fact the storyline was basically "You are stuck here. Now fight" and that the characters powers seemed to be all over the place (Luffy repeatedly failing to hit that one guy on the deck of Puzzle's ship, for example) made it feel like something out of Bleach or Naruto.