Well, since this thing is still alive, I’ll share my experience:
I was once a very devout TBT/functional bro. I mean, it seemed to make sense, train more often; make more gains. And in the sense of what I like with training philosophy, I am similar to MODOK in that I like frequency.
Anyways, I trained TBT 3 days a week, bumped it up to four days a week, and, aside from some 20 lb of newbie gains (which, I think most people can get by just looking at weights for the first time…), I didn’t grow (eating was a factor, but we can ignore that for the time being).
Then I saw great lord MODOK’s thread on frequency, and saw that he had similar thoughts, and did a 3-way, 2x week thing. Thinking that he seemed like a pretty cool guy, I gave it a try.
Long story short, I gained 10 lb in 4 weeks by switching to a split. I also fully believe that you can’t really give any other big movements on the same day the attention they deserve (in TBT), as, once you start moving “heavy” weights (assuming the typical legs, upper push, upper pull template), you simply can’t bench or row with nearly the same intensity as one a JUST bench day or anything.
I do, however, believe that TBT-type stuff has merit in terms of like pure strength or what-not, but this isn’t the pure strength forum, and what I believe doesn’t matter a whole lot.
And as C_C mentioned in another thread, even assuming TBT could pack on mass at an unprecedented rate (he himself didn’t mention TBT specifically, he was talking about programs that favor “as much mass as possible in as little time”, unless BBB is considered TBT), you wouldn’t be packing on “quality bodybuilding mass”, that is, you wouldn’t be building a nice, symmetrical, aesthetic physique with just compound legs, compound upper body push, and compound upper body pull every day.
TL;DR: At the very least, not good for the purposes of bodybuilding.