If you read Fred Koller's book on "How to pitch and promote your songs" (that's actually a very positive read!), he states that you should not give up all your publishing, and surprisingly, not even as an unknown writer without track record!

You should certainly not give away your songs with contracts without reversion clauses, and it might even make sense to be specific in the criteria on HOW the songs revert back to you (as there are some scams here as well).

A company with just a MySpace prescence, already ring an alarm bell in my book! Everyone can get a company no, and create a quick MySpace thingy, but that doesn'nt say ANYTHING about the company's status nor legitimacy.

Those things alone, unless I knew the person who runs it personally, would be a dealbraker for me..