Can you please weigh in about carbs/net carbs?  I am trying to keep my carbs under 20g per day, so I assume a bar like this is a no go (21g of carbs, 17 of which are dietary fiber), but want to make sure I am interpreting the 20g carb goal appropriately.  Thoughts?

Its a personal decision you have to make - there are plenty on both sides of the fence.

But from Atkins - a little info:

Fiber: A Special Kind of Carbohydrate

Perhaps your grandmother called it roughage; physicians call it bulk. No matter what it’s called, dietary fiber traditionally used for relieving constipation is an important consideration when changing the way you eat to a lifetime of healthy eating. What exactly is fiber? Simply put, dietary fiber is the indigestible parts of plant cells. Although it is a carbohydrate, fiber does not convert to glucose and thus does not raise your blood-sugar level the way carbohydrates typically do.

In fact, fiber actually slows the entry of glucose into the bloodstream. This, in turn, reduces the blood-sugar spikes that cause insulin production and encourage the body to produce and store body fat. And by slowing down food’s transit time in the digestive tract, fiber helps you feel full longer, resulting in fewer food cravings.

But that’s just the beginning. Fiber also:

• Binds to cholesterol in the intestine, helping rid the body of it.
• Absorbs and then eliminates bacterial toxins in the intestine.
• Reduces the likelihood of getting diverticulitis.
• Speeds the excretion of gallstone-promoting bile.
• Supports the immune system by crowding out harmful bacteria in the colon.
• Bulks up the stool and make it easier to pass.

Fiber-rich foods include vegetables, nuts and seeds, fruit, beans and whole unrefined grains. You can sprinkle bran over your vegetables or blend flaxseed meal into a shake to get an extra boost of fiber. Also remember that you need to accompany any increase in fiber intake with plenty of water.

If you haven’t been eating significant amounts of fiber, increase your intake gradually to allow the intestinal tract to adjust.

It might be heresy, but I lost quickly and steadily while eating one or two of these per day.

I am in maintenance now, and I still have 1-2 a day as snacks or meal replacers when i'm on the run.

I am pretty carb-sensitive and they never stalled me.  I track everything, but I chose the "net carbs" route.

I can only say that everyone is different, and these might be a trigger food for you, or the particular makeup might not work.  My recommendation is 

1. track everything

2. introduce new things like this slowly

3. experiment and track results

4. if it ain't workin' stop doing it.

I've done tons of experimenting and have tried a lot of different things.  I believe I've been able to simplify my food choices that way and get down to what works and what doesn't.

For me, quest bars give me a lot of protein, don't trigger me into other carb cravings, and I tolerate them well.

Your mileage will likely vary.