3.9 A1200, every week. 3.9 A4000T, not very often. Various flavours of UAE (My phone, my Xbox, and my dreamcast). Try out Aros now and again.
On the subject of user numbers, we need to remember that a large number of Spanish and German users have their own forums. Perhaps other Euro nations as well. There are also users who do not bother with forums. I've worked with quite a few Amiga users who are happy using the software from the past, and have no need of come on to a forum.