Can't comment on all as I've only done 2 but doing personal tax and then business tax made a lot of sense so I'd say if doing one of those 2 do the Personal Tax.
On the other hand I would choose those that are likely to be more useful. If you're doing mostly work with Ltd companies for example then business tax is the better choice.
AAT Level 4, MAAT ACCA in progress F4- Passed Aug 2020 F5- Planned for Dec 2020 F6- Passed Sep 2020 F7 F8 F9
I did cash and treasury management and credit control modules. I then changed class for the start of the core units and that class had all done the tax units. I think the tax units have better pass rates so you could argue that they are 'easier' however I think the cash and credit modules ease you into the core modules because a lot of the content within them is covered across the core units (e.g trends, cash flows, performance management ratios). The cash and credit exams are also in the same format as the core modules in the sense that they contain written questions. Those in my class that did the tax units are struggling with the writing content now.
Answers
On the other hand I would choose those that are likely to be more useful. If you're doing mostly work with Ltd companies for example then business tax is the better choice.
ACCA in progress
F4- Passed Aug 2020
F5- Planned for Dec 2020
F6- Passed Sep 2020
F7
F8
F9