I have noticed that different supplements have different effects. It most depends on the kind of fiber your taking. Many people find psyllium can really block you up if not careful. I have found that fiber that can be easily mixed into my smoothy works the best. It also makes me lose my appetite between meals when I use it this way.
Another thing I found really important is using organic fiber when I can.
Anything with flax seems to work the best for me and there are so many health benefits.
I recently read a book that said 35 grams of fiber a day is optimum for women to lose weight. This had helped. It is much more fiber than most of us get and supplementation really helps.
I'm sure you know, you need to drink alot of water with them.
I'm not an expert but those are my thoughts based on my research and experience.
Love to hear how it works for you!