I love statistics so here's some numbers on the Fedora Unity Spins for Fedora 7 and 8:
Our Fedora 8 CD Set jigdo has been downloaded over 350 times, while our latest Re-Spin has been downloaded almost 300 times.
From the raw numbers I can conclude though that not everyone who downloads the .jigdo actually uses it and downloads the corresponding templates. What we see is that 300 downloads started for CD #1 (both architectures), which is obviously the only disc everyone needs to download. The issue might be that people don't know how to use it, I'm not sure. For our multi-ISO .jigdo files though we do not have a good GUI client at this moment, so I'm hoping pyjigdo improves in that aspect during the Fedora 9 development cycle.
Also, while 300 downloads have been made for CD #1, only 115 requests have been made for the other 4 to 5 discs in the set. This indicates almost 2/3 of all people that download CD ISO images want a single CD to install Fedora. As said before, the next thing is Single CD Installation Media (ideas are still welcome).