The only problem with this is that the person on the other side of what you are sending must have the tool as well. However, at the top of the encrypted email there is a link to download the tool. Also you must both have the same passwords in your password lists. It's very effective when you are both on the same page with the encryption, especially if you send files that have been encrypted with A-Lock. I use it all the time to encrypt stuff.
Yes 7-bit blowfish can be broken, but it takes a substantial amount of time and computing power to do so. But this is only with software that guesses at the passwords over and over again until it gets the right one. Just like anything else, good passwords are key (no pun intended).
Otherwise it's easy to use, and can be a very powerful tool. One of the cool features is that you can just type in your email in a text box (AOL, Hotmail, Yahoo, etc.) and click the icon and it's encrypted right there before you send it.