I have not tried them but they have gotten a terrible reputation in the low carb community for being a scam. You can read some of the evidence yourself and decide.
I was thinking of trying them but I haven't yet. I tried Ezekial breads but they also seem to spike me most of the time. I think it is the wheat maybe, I'm not sure but I have some type of reaction to wheat/gluten most of the time. I'm trying a gluten free approach to see if it helps me.
I haven't tried gluten free breads yet because they're so high carb but I have tried some gluten free crackers. I don't think it made any difference though, sometimes they seem to spike me and sometimes not, since they weren't the only carbs I had I'm not sure.