First of all, it's expensive for ice cream. But you're paying for the freshness and the experience of watching the process, which is pretty cool. You get to choose the flavor and what kind of milk you want in it, as well as toppings.
We tried the green tea, which was good, but probably didn't justify the $8 price with tip. The worker actually messed up our first batch, flipping a large chunk off the actual ice pan onto the counter, so she whipped up another and gave us both.
I would definitely go again, but I would go knowing that it's more about the novelty and experience than the actual ice cream. Maybe other flavors have more of a wow factor. It's worth checking out if you want some ice cream.