Arabic is supposed to be harder!(on par with Latin) I did some Arabic a while ago. I didn't do any GCSE stuff. This was at the local "school" if you like. I had far, far more motivation to do Arabic over urdu.
I can speak hardly any urdu/punjabi and Arabic is a language that would really help in the future, if working in Dubai etc.. , the Qur'an is written in Arabic and there is a lot of scientific text in Arabic. I highly doubt I'll be working in Pakistan/Bangladesh any time soon. I dropped it after a while because I had other commitments ie: actual GCSE's.
It's supposed to be harder, as it makes sure you use both sides of the brain intensely, making it apparently the hardest "live" language to learn. ie: Latin is a "dead" language
Also, urdu would probably have as much worth as another language, though some uni's may not like it for whatever reason.