Yeah, most guys past 4.0 aren't in their martketing wheelhouse, but they do good stuff for most adult rec folks. I just don't pay for stuff online like that, but love they do good free things too. I pick up little tips here and there watching.
It would be a lousy business model to target the advanced market, since that's only about 3% of USTA [ie >= 5.0]. I'd say their content is great up to and including 4.5. Even they admitted that beyond that, those players are going elsewhere.
Probably. Like others, I've never bought any of their stuff but I love their free videos. Also, I'm a coach myself so it'd be weird if I was paying for coaching advice from another coach, haha. But I've even met Ian, seems like a very nice and knowledgable guy. I agree with S&V... probably anybody 4.5 and under could benefit from his paid stuff, I just can't say for sure since I haven't seen his paid stuff.
I have the Chaos Doubles and a few others. It's very good, though a bit overpriced. The free stuff is about 15% of the total, and you'll never know what you are missing. He is an excellent teacher. Each course helped my game. There is lots of free youtube videos from semi-pros or others but it is not as professional as feeltennis or essentialtennis.
The most useful of all is the "shadowing" in doubles clip, which should be required viewing for anyone on a doubles team. Practically nobody moves in the rec doubles I play, even good players.
The in-person sessions are unbelievably expensive, at $8000 for a weekend (up from $5000 for one at Indian Wells).