I have got some issues with the surface tools:
1. they are stuttering and a bit unresponsive (triangle count 3200000)
2. If you release the mouse button you have to wait a bit
3. If you don't wait enough you getting artefacts like these (red arrow)
Hopefully you can fix these points because I really like those tools and there are working in some situations better than the voxel tools
Oh, my specs are:
Intel quad Q6600 @2.8
Nvidia 8800 GTS 640MB
4 GB RAM
Win XP with 3GB Switch