There are several things to like about the FS5 but the bit rate of the codec is so horrendous to us that we can’t bring our selves to pay that much money for such a meager bit rate (100Mbps).
News Shooter has a review of the Sony FS5 that is worth reading:
Finally there is a large sensor camera that you can use for broadcast work as efficiently as a handycam. It has small but significant improvements over the rival Canon C100 mkII. The key differences are in higher bitrate HD recording, the 4K option and super slow motion options.