I gutted my finished attic; tore out the fiberglass; and had it spray foamed. The difference is incredible. My biggest concern was radiant heat, and it's helped immensely. On a sunny 90 degree day, it was too hot up there to use it at all, and with 4-5" of open cell spray foam, it's not much warmer than it is downstairs on a hot day. I didn't find the price to be that unreasonable.