If you have a secure BTC wallet it will also be secure for your MSC.
At this point there is no MSC wallet yet, they are simply in your BTC wallet.

As long as you have the private keys to your wallet you can have your mastercoins in there as well.
You shouldn't pay extra for information that is free to find.

If you have questions about Mastercoin you should ask them in this thread:
https://bitcointalk.org/index.php?topic=265488.2560