[bobbruno]

That "very excellent tai chi fighter" is, if I'm not mistaken, Chen Ziqiang - son of Chen Xiaoxing and nephew of Chen Xiaowang, part of the family that the Chen style comes from. He's the current master of the original Chen village school of Taijiquan, one of the biggest winners of Chinese push hands and wrestling championships (for his weight) and one of the most serious practitioners I know. I've been there and seen it, it's lots of heavy exercises, hours of daily practice and sparring.

He is indeed excellent, but if that is the level it takes to use Taiji in practice, you won't find many people in the world who can.

[leashless]

I have heard it takes roughly ten years of practice of tai chi to be able to fight reasonably effectively using tai chi principles, assuming you have a very workable base of kung fu or something equivalent established (say ten years) before that.

If it's just about learning how to fight really really fast the WW2 combatives courses seem to be the best available system. I don't think any martial art is suited to the speed and directness of modern life.