Bittorrent Chat works differently from Tor. The protocol is not yet finalized but we'll make sure to have external security experts review it to ensure that we deliver on our promise.

Getting to how-easy or how-difficult the installation is, is an endless discussion and is very subjective. One thing that I should add though is that something that might be super easy for you might not be as easy for 99% of Internet users (which is bad for a messaging app specially since you are likely to have friends whom you want to talk to in the 99% category). Installing/configuring a GPG plugin is likely to be one of those.