We just finished our own house using a brand of these forms. The results were quite satisfying. Be sure when setting the forms that they are adequately braced to avoid blowouts during the pour.
We used a brand that was available at the local construction materials outlet. I would suggest that you see what's available in your area. There are a number of brands available, all appearing reasonably similar to me. I expect that skilled installation is at least as important as the particular brand.
The one surprise was that we had to sheetrock the inside of the wall for fire resistance. The forms are flammable, and, uncovered, could create a dangerous situation an a basement.
