Meh. It's more gimmicky than anything. Yes, it's kind of cool that you get to make up your flavor on the spot, and I appreciate the entertainment value of the nitrogen cloud rising off the stand mixer.
But the ice cream itself was icy and hard. Ice cream benefits from churning, breaking up ice crystals and incorporating a little air for texture. The flavor was on point (I went with banana in a normal dairy base) and the marshmallow sauce is not too sweet and reasonably thick. But the mouthfeel really lost me. Given the price point (kid size begins at $5), I would go with Churn any day.