I found Business Finance tough since it's quite a loaded subject - it teaches the basics from each of the core level 3 finance subjects. There's a lot to learn and in detail.
Introductory Personal Finance has probably been the easiest subject I've taken.... Lectures were very boring, you don't learn anything that interesting tbh, you only scratch the surface of personal finance - you won't learn anything that will help you substantially in your finances. I think what you learn would depend on who the lecturer is though, I had Carsten who was pretty relaxed and liked to make things somewhat more interesting. He made the subject very un-finance like based a lot more on the behavioural finance side rather than conventional finance. i.e. you learn about cognitive biases.
I'd recommend Business Finance, it's a lot more useful even though it can be boring.