asterisk users - Jun 2012 - Asterisk 1.8 / sending fax / spandsp

Hi,

I need a fax-send - setup. I read the book "Asterisk The Definitive 
Guide" chapter 19 (fax) and found 2 options listed there.

1) Using spandsp.
2) Using FFA (Digium Fax For Asterisk).

But the book nor any other article I read point out, what the 
differences or drawbacks are.

Does anyone of you have experience with one or both solutions?

We use:
- Asterisk 1.8.13
- Sangoma AFT A104d (germany, E1)
- libpri
- DAHDI 2.6.1

Thanks for any hint.

-Thorsten-