I went with the Owens Corning 703 equivalent, John Mansville 814 for my studio. I ended up doing it twice and filling out my main listening area with some first order reflection treatment as well as some cheap 'studio foam' from amazon to kill some of the reflections on the ceiling. I checked all over as you are likely doing, but nothing really compares to spending the money on the real deal.
I paid around $80 for 6 sheets of 2" thick JM814 and extra in supplies such as wood for the frames and screws and fabric, etc. Comes out to something like $160 or something for 6 absorption panels.
Denon AVR-X1200W, Polk RTi 8's, CSi 5, FXi 3's, Sapphire Satellites (front heights), Martin Logan Dynamo (2)
PS3, SNES, XBox360, PC, SNES