Economics has basically no math in it. Eco is a lot harder than business but is far more interesting. It requires a lot of work and you need to be good at essay writing, short answers and knowing heaps of stats in order to do well, but it is quite rewarding. If you don't like eco at the start then maybe change subjects because a lot of people who I know didn't like it at the start never started liking it.
Business studies is really easy in comparison, so while eco requires higher order thinking and harder questions, business just lets you regurgitate the textbook to get a band 6, nothing else required really, apart from your case study which you can make up if you want. Business can be quite dry and content heavy, but it depends on your attitude, because it can also be quite interesting at the same time.
If you are naturally good at stuff and want to pick a strategic subject to get a better atar then go business, because the smaller workload and higher marks will pay off.
If you want something more interesting and fun, then go with eco. It scales better, but the effort to get the same marks is disproportionally larger I reckon.