OK. Ice Monster was pretty good. I always enjoyed eating there.
But it was not the best shaved ice in the Taipei metro area. It was one of the best, sure, but come on.
Like Dintaifung or that lady in Xinzhu who sells popcorn (any local will know what you mean), it was considered the best because of its fame, not necessarily because it was the best. I like Dintaifung, though I think they are overpriced. Shanghai Dumpling on Minsheng E. Road (east of Dunhua) is just as good for 1/3 the price.
And as for Ice Monster, again it was good. But if you want fantastic shaved ice, then you need only go to Sugar House in Nanshijiao night market (The market is T-shaped - it's on the base of the T, a left turn about halfway down if you enter the market from the MRT).