I recently worked as a teaching assistant on an expensive and well-regarded data science bootcamp course. I did this primarily because I was curious what classroom-based training in data science was like.
I found it much less useful than online materials. It seemed like the primary benefit was just that once you've stumped up several thousand pounds, you're motivated to actually show up and concentrate. And you also get to meet some people with a common interest.
But the quality of teaching fell well below the standard online (not surprisingly, when online you have access to lectures by superstars like Hadley Wickham, Peter Norvig and Andrew Ng, with lectures that have been carefully recorded).
And on top of that, it's not a great use of time. A half hour to commute to get to the lecture. Then the lectures being in 'real time'. Online, I find myself running video lectures at 1.5 or 2x speed for large portions of the material - the 'filler' - and then having to watch, re-watch the hard concepts several times at normal speed and pause just to think.
I found that at the end of the classroom course, I had developed an awareness of the existence of concepts and techniques, but not really an understanding of them.