I've had fairly good results, but I mainly use it for off camera fill flash with ambient light eg outdoors post wedding shots
I only have 1 sb800 so I couldn't use it for much more although have sometimes used a lastolite reflector on opposite side
I have NEVER used it as the only light source (doesn't mean you can't, just that I haven't

)
Basically I put D70 in Commander-->ttl and maybe dial in some minus FEC (aroun -1.7 using flash button and front command wheel on camera)
if it's a little trickier, for example, I want to underexpose background, then I might go to commander-->AA so that sb800 only exposes for my aperture and uses it's onboard sensor, not what I'm doing with ambient light, and use spot metering for background
And if it's REALLY tricky, I go to commander-->manual and then take 100 shots (lol) varying aperture (for flash exposure) and shutter speed (to compensate aperture) until I get it right!!
Can't post an example because I am at my day job being a mild mannered metrologist at the moment (well, I am at work but surfing photography forums!!!)
However, there are heaps of good examples at
http://www.pbase.com/dlcmh/d70_amazing_pics
hope this helps a bit
Kris