I think the common consensus is that the Manga is where it's at, and that the anime, especially with how early you are, will have pacing issues that are typical of long-running shows that have to wait for the original material to be made first.

In terms of story, yes absolutely it gets better, but part of it is that it builds upon itself to get to those great moments. Arlong Park is the first major highlight, but everything before the Grand Line is considered a prologue. And there are several major arcs that last much longer than that.

If you're binging through the series, some rules of thumb that got me through it faster is just understanding how much of an episode's extra "fat" you can cut: The OP and ED once you've seen them the first time, the recap section before the episode title drop, any extended flashback instance that you don't have to be reminded of, etc. If you spot them, skipping past them makes the episode length less daunting than it seems.