Yesterday i2pfox version 6 was released. The most important change is that it comes with an installer that installs a firefox with all the needed plugins and options in a directory you choose. I only tested the Linux version with ubuntu. All the plugins as described here come in their newest versions, and, when you compare version 5 and 6, InfoRss, wich enables you to display RSS feeds in the statusbar, and Torbutton, a plugin for TOR, have been added.
The only disadvantage of i2pfox is, that it’s “close source”. You can only download binaries – so you can’t be sure if it is really so anonymous as the author says. You have to trust him or don’t use it.