I have a couple of friends who take music, and they say it's really hard, even the people who have high grades on their instruments are struggling to get top marks. I take drama and I think it's very enjoyable, but it's a lot more work than people expect. Neither are doss subjects so don't expect them to be easier, but in my opinion it is nice to have a break from written work in drama (the majority of the time anyway). Just choose whichever you think you'll enjoy most.