It contains a very unpleasant bug. When encountering a Usenet article that has a CRC error or is malformed, the back-end of SABnzbd crashes internally. This results in a gradual reduction of download speed until speed is 0. Only a restart will fix this (possibly only temporarily).
Sorry for the inconvenience, there will be a 0.7.9 release as soon as the first bug reporters have verified the solution to the problem.