Always consult the Owners Manuals and FAQs first.
FM3 information is being added as it becomes available, but it's preliminary and not final until release
Yeks Guide to the Fractal Audio Amp Models
About the guide
Forum member Yek (Alexander van Engelen) describes each Amp model in his Guide to the Fractal Audio Amp models (PDF).
The guide was preceded by a series of threads on Fractal Audio's user forum. Forum member Simviz assembled the contents of the threads into a PDF guide.
The guide is updated periodically.
Brief information about the Amp models is also available on this wiki page: Amplifier models list.
If you find the guide useful, consider donating to a good cause.