What I'd really like is some user feedback on the board?
Great hardware! The driver support is still fairly limited. 100% support ATM is limited to AFAIK:
Voodoo 2000/3000/4000/5500 (get the 3000, specific support)
RTL8029AS 10Mbit ethernet
Catweasel MK4
Is it any good, does it take three weeks to get going?
Not really. You should be able to get it up in a night. If you get one, come here for guidance as the software that shipped with it new is outdated. There are plenty of Prommy users here, as I sold most of them one ;-)
What is the support like?
You're looking at it, Amiga.org is the place. The community is the best place for support.
Are they still made?
No. I secured the last of them from Matay in ~2003 and sold my final ones in late 2004. You may be able to find the odd new one in a shop though, try Amigakit.