I've bought it and love it.  My landscapes have really come to life now.  I'm working on something that is mostly created with GeoControl at the moment.  Hope to finish it by the end of the week so will post it here.

I do find it slow but my system is rather old and low spec now... two years old.  Painting with the brush sometimes gives odd square marks, it's not quite as smooth as using the Bryce Terrain Editor but that's more than made up for in the stunning realisim you do get and the problems can usually be undone.

The seamless option is not as good looking as using tiled terrains in Bryce.  I currently have two sets of four terrains and I had to position the camera carefully and modify them in the Bryce Terrain editor to get them to look a bit less repetative.

Despite any small comments like that though, I think it's well worth the money.  I've been frustrated for a long time that nothing I did made my landscapes quite have that 'real' feel and this has been the tool that I've been waiting for.

GeoControl has it's own forum set up so hope to see people talking more there about fine tuning the effects as I feel there is a lot to learn in it.

Kathy