I think the lightsphere is AMAZING....
Indoors you will light up a large room with 360 degrees of directional diffused light. I have lit up entire graduation halls (large rooms) with the lightsphere. The larger the room, however, the more the light becomes more "fill flash" and less dominant.
You wont get shadows under the eyes and your subject will be exposed the same as the background. It's very cheap ($39 USD) and wont break.
Outdoors, I use it only for portraits. From far away it wont make too much difference, but within 10 feet, it will. I typically put a flash on -1.7 TTL to start out as fill flash...the lightsphere, I believe is -1 stop, so I go about -1 to -.7 and you do get a better diffused fill flash.
It's the best purchase I have made in a long time. I rely strongly on the ligthsphere for all my weddings.
Get a clear lightsphere, a cloud lightsphere, and an amber top and you will be all set.