They have a decent number of flavors there, and they are made with tea and milk and bubbles (tapioca), so they're "real" in that sense. They have two sizes, $4 and $5.
I got my standard variety, the cold black-tea, milk, coconut and bubbles. The bubbles were overcooked and way too soft, just like in Vancouver. The milk tea itself was ok, but they had no machine so they actually shook it up by hand. Tres ghetto. It wasn't gritty, though, so that's one up on the place we went to in Chinatown the day of the dim sum meet. There's a crapload of ice in it, though - at least a third of the cup was ice. Even after it's melted a bit it's still a good quarter of it. Bah.
Overall, I'd say they're passable. Since there's a Saint's Alp so close, I'd recommend just taking the hike (it's over on 3rd Avenue, around 9th or 10th Street) over and getting one from there. If you're not in the mood for a hike, though, it'll suffice. It's a bit pricey, though, for just "decent".