@dunc, OpenX is still a beast. On the newest version, make sure you delete the "OpenX Market" plugins, or it's going to start sneaking it's own ads into your campaigns if you let it.
But when it comes to ad serving, unfortunately OpenX is one of the better ad servers, but it is totally and utterly geared towards mainstream. For us "adult" types, you need a bit of a different setup if you want your stats to eventually make sense
(at least, in my humble opinion).
I blogged a bit about OpenX
on my blog using my own setup as an example.