When first announced there were certainly a few very noisy detractors of TT:120. Some seemed almost mortally offended that such a thing even exists.
Don't hear them so much nowadays. Even so, the two closest stockists to me still don't stock TT:120 on the shelves. They'll both order anything I want from both Hornby and Peco, but then I may just as well go to any other online retailer, so they lose my custom. And I have told both of them this.