I think each product has its goods and bads.
I like Buffer as you create your schedules and it finds images from the posts. It’s not the most powerful but for my needs is good. I like their analytics too. But if you need to do complex things might be other alternatives.
I think the manual/native app scheduler is only good if you using one social media, at the moment that you need to deal with more than one profile it’s quite time-consuming.