I can't comment on favorite, but I hate anything that requires a proprietary bit exclusive to the fastener manufacturer. The contractor that built my barn had an affinity for FastenMaster's HeadLOK fasteners, there must be hundreds if not in the low thousands of these in my building (at least $2k worth). The head drive on these is a proprietary drive called SpiderDrive. The bits are awful quality, they give you 2 per bucket of which is usually just enough to get you 1/2 way through a bucket before the bit wears to the point of poorly engaging the fastener or simply breaks. And the poor drive design also means that plenty of the female drive ends on the fasteners are worn simply on initial installation.
The HeadLOK Screw is a code-compliant flat head rigid foam structural wood screw for attaching deck framing, requiring no predrilling. Learn more.
www.fastenmaster.com
No idea why he doesn't use FlatLOK instead, which has a Torx variant, at least then you can source higher quality replacement bits easily.