I sold my 70-200 in a financial crunch about a year ago. As I bounced back later, I replaced it with an 85mm 1.8 and a 300mm 2.8 (not the 300mm you are probably thinking of, but that's a digression for another thread).
So between the two lenses under discussion which one would I buy the next time I have an accumulation of "lens money?" It would be the 135, hands down. I had the 70-200 or its predecessor, the 80-200 2.8L (and before that a Nikon 80-200 2.8ED) and used that type of lens pretty much every single day I took any pictures at all for nearly 25 years. When I had to sell it I was kind of panic-ed at how I'd get along without it. I'd never have believed it a year ago, but I still don't miss it very much at all. A 70-200 zoom is no better than third place on my list of "lenses to buy next."
I rent the 135 periodically. One weekend last spring I had one to shoot indoor tennis in a dark, low contrast tennis dome (inflatable structure). The day turned out to be unexpectedly warm and sunny, so they moved the match out the back door to the outdoor courts. I no longer needed f/2.0, but I had the lens, so I used it. I dropped the ISO down to 100 and shot wide open or nearly wide open. My client for that job is a man of few words and seldom comments unless my work misses the mark in some way, but that one time he sent me a short email to say words to the effect of "I don't know what you did but the shots from that match were a cut above the rest."
That confirmed my feeling that the 135mm 2.0 has a look and feel all it's own. In a perfect world, I'd probably own both the zoom and the 135, but the 135 would definitely get bought first. I'm not a prime lens snob, and that's my use case alone. Either lens is a great asset, and it's a very personal choice for each individual photographer.