I nixed the Atkins bars because of the sugar alcohols. It definitely caused a spike in my readings. I'm trying recipes with ingredients that I know wouldn't affect me in that way.

Others have covered the sugar alcohols, my experience is the same. I've made some desserts using Erythritol and have no blood sugar spikes with it, its the only one I will use.

I've also seen others talk about issues with these super high fiber items, whether the label is a flat out lie or what I don't know... but seeing something that claims 25g carbs/16g fiber that's trying to replace something that's normally carb heavy is a big red flag to me and I may try it but would carefully check my sugars afterwards. Another example of this that I see pop up a lot are some popular "low carb" tortillas that claim to be like 90% fiber made by Mission. Some people seem to do ok on them, others report problems.

The previous poster mentioned making Reece's Cups, I've been making these:

http://screwedonstraight.net/keto-diet-peanut-butter-cup-fat-bombs/

The recipe mentioned "sweetener to taste" and suggested splenda. I replaced that with 2 tablespoons of Erythritol instead and they are amazing. With the type of peanut butter and dark chocolate I used, mine came out to 4g carbs each instead of 2g mentioned on the site, still pretty good