I don't know how competitive they are. I applied for 2 for the same month block to ensure I would get one, and was offered the one I wanted so I withdrew my applications at the other. Incidentally, I was not offered an interview at the one I withdrew my application from, but I doubt that had anything to do with it.
Remember, you are paying this institution, and likely they have multiple spots over multiple blocks. Certainly the first block of M4 will be the most popular, and you will likely be "competing" with the university's own students. I haven't met anyone who got "rejected" from an away application...they just may not have gotten the specific time frame they wanted.
So I guess my advice is that if you absolutely can only do the away during a specific month, apply to at least 2 to ensure you at least get an away. I sincerely doubt it will hurt you to be accepted and then have to turn one down...that is the nature of the business.
