Here are some reactions:
"Can be used to manipulate audio into weird and wonderful sounds. Highly useful within sound design." (filmcrewpro)
"It feels like a cross between SoundHack, Syd, and Argeiphontes Lyre. The sounds I'm getting out of it so far have been killer. … blows the mind" (Mac OS X Audio forum)
"resource-rich and highly recommended for anyone looking for some wild ways to bend, fold, spindle, and mutilate audio." (Dave Phillips for Linux Journal)
A peculiarity is the fact that all modules operate in non real-time. This allows on the one hand to access the sounds in a non linear fashion, but also facilitates complex calculations which even today would not be possible in real-time speed. There are many processes, however, which run hundred times faster than real-time, opening intesting applications for the embedding (using an OSC interface) of FScape in real-time improvisation or installations. For instance, in my piece «Inter-Play / Re-Sound», parts of the past improvisation – which is record continuously – are picked out, transformed and re-injected, after only a few seconds of processing, as new material for the ongoing piece.
Although many modules have close relationships with particular pieces I wrote, they nevertheless form a universal toolkit for any work on concrete sounds. FScape is used by composers worldwide and is also suitable for teaching, as the basic setup is fairly simple and some modules quickly provide rewarding results with minimum prior knowledge. At the same time, the repertoire is virtually unlimited, as the modules can be combined in ever new ways (e.g. a sound could be first translated into the Fourier domain before applying other algorithms which you would normally reason about in the time domain, or processes could be repeated over and over again).
The following 14 minute screencast should allow you to get started with FScape: