you are right, but getting never 100% security with our computers, you should state HOW secure it is, and there's no standard i know to measure such security.
so having no good way, i just say "it's okay" (secure) and "not okay". Highly debatable, but it's good for non-techies (and it's short!).
Techies will be good to value this security on their own, and relating it to their needs. 
Just at a glance, i would say a man-in-the-middle attack should be hard enough with such configuration. Any opinion on this is welcome.
I think this software is the best you're gonna find for the money (FREE). If there's a feature you don't like or a problem with it, why not spend money and have someone fix it, or donate to them and help find an answer to the solution.
@rejetto...software is great! Helps me access my files every day. I appreciate the hard work and effor on this.
John