I like it and I don't like it. I like that its a slick shortcut. I like the simplicity and sneakiness. I don't like that you trap your hand and open a window for a sweep or guard replacement. His s mount is so wide.
I prefer to s mount the way Zog teaches. Much tighter and it Sets up more options. Lotta guys will try to escape under the leg anyway and give up the triangle for free without me having to trap my hand. If not you can deep hook to spiderweb. Or clear the arm and set up monoplata....or get to mono mount and work rubber from top.
I think it's a move that works, no doubt. But it's also a move that, if you aren't lightning quick, you could lose position. Not worth it IMO. Like I said, I'd rather take my time to work proper s mount and take the options that gives me. I learned a while back that it's better to work a path than take a shortcut. Just my preference.