I make a yummy chicken & shirataki noodle soup with them.
We had a conversation about them in the recipes thread, and StrugglingNicole said that they aren't really on our plan:
I don't know if you got the answer to this question yet or not, but I took a shopping class and asked about these noodles. The answer I got was that they are on the vegetarian menu, so if that is what you are on they are approved. However, if you are not on the vegetarian menu they are not OP. They are a great maintance option, I'm told!
But to be totally honest, I still eat them about once a month or so, when I get a craving for a noodle soup. Personally, I think if you can eat them occasionally without it affecting your losses, then go for it. I occasionally slide not-totally-OP foods into my menu once in a while (like cooked tomatoes sometimes) and it hasn't affected my weight loss yet. If it does start to affect it, I'll quit straying and stick to the plan as is.