I'll give you four options, pick one that fits your preference, although I highly recommend not picking option 4 since it's the least enjoyable. At the same time I can't force you not to pick it so it's your choice.
Option #1 (Watch the anime till the enies lobby arc and then switch to the manga)
You need to realize that the anime at the moment is covering one chapter per episode which is awful. They kept this trend up for a long time, during the start of the enies lobby arc (episodes 264 - episodes 312) is when they started doing the one chapter per episode pacing. However, before that it was like 2-3 chapter per episode which is really good. If you want both experiences, you can watch the anime till the enies lobby arc and then switch over to the manga. That would be good since you're getting both experiences and you're not missing out on the anime when it was good.
Option #2 (Watch the anime till the time skip and then switch over to the manga)
Personally, I watched the anime till the time skip and then switched over to manga but even then it was really enjoyable. I didn't notice how terrible the pacing was because I was watching 20-25 episodes a day when I was getting caught up. It's your choice, the only flaw I can really think of for the OP anime at the beginning. They skipped out on the scene on how Luffy got his scar. (which is covered in chapter 1 so if you really want to watch the anime then just read chapter 1 first and then go watch episode 1)
Option #3 - Manga only
Then there's the manga only option, arguably the best one. However, you will be missing out on the anime's OST's that add on to certain backstories/scenes that make it that much better.
Option #4 - Anime only (I don't recommend this)
Yeah this should be an obvious one to avoid since I told you the problems of the OP anime currently. Not to mention the animation/art is pretty inconsistent at the moment and fails in comparison to the earlier parts of the OP anime.