I'm doing OCR Geography (started A2 about 2 weeks ago) and it's reasonably hard. But I like a challenge, and it's interesting as well. I would rate it as my 2nd hardest subject (after Biology).
It covers a board topic area from different ecosystems, reasons why a country is poor/rich and how it varies from regions, how landscapes change over time due to processes, and so forth. I admit there was a lot to memomise, though.
However, if your other subjects are of the science/humanities kind, then I recommend Geography. The physical and human nature of Geo would mix well with your other subjects.