Hi. I'm at Aberdeen doing an LLM in international commercial law. The LLM people just announced that they are thinking about offering a commercial arbitration class starting in October 2010.

I think it really depends on your interests. You should take a look at the course calandar online and see if the courses within the program appeal to you. Some specifics about the Aberdeen LLM in private international law are at: http://www.abdn.ac.uk/law/graduate/pil.shtml. There are also other classes for the program, but their availability varies from year to year (e.g. next year I understand there will be an arbitration course and this year there was a second choice of law class). I do not know about all universities, but at Aberdeen there is room to take one class from another area if it appeals to you.

As for being beneficial in practice, I think an LLM always looks good to employers--more knowledge is rarely a bad thing. :)