I purchased the orbis because I like the "shadowless" look of ring flashes and the centered specular highlight and edge falloff these kinds of lights produce. It's also an excellent type of light for fill flash. Finally, the orbis can be used off axis/off camera just as any other light source, and because of its size, creates softer shadows than the bare speedlight when used close to the subject.
The orbis ring flash is a great idea that unfortunately falls short in a major way, holding it back from being completely usable.
There has been a lot of talk about how the orbis will not hold your speedlight securely. Since that topic has been covered I will only mention that it is a big concern and great care must be taken to avoid an accident.
For me there are two glaring issues with this product. Although you can learn to hold the orbis and the speedlight in such a way as it won't slip and fall, the fact that you're holding them with your focus/zoom hand is a problem...for focusing and zooming. Enter the orbis arm product.
The solidly constructed orbis arm aims to free up the photographer's left hand returning it to it's rightful place of zooming or manually focusing. The arm is attached to the camera and the flash (with orbis) is attached to the arm by way of a TTL hotshoe extension cord. Finally, the TTL hotshoe is attached to the bottom platform of the arm. (Optionally, some camera and flash combos can use the manufacturer's wireless flash option rather than the corded method, but I did not experiment Nikon's CLS with the orbis). The arm can be adjusted vertically so the ring lines up with the lens.
While the arm itself is solid, any forward or side to side tilting of the shot puts a lot of force on the TTL hotshoe and the lower part of the speedlight, both of which are made mostly of plastic! There is quite a bit of play at the orbis end of the "tower" (TTL, speedlight, orbis) and when tilting the camera down or sideways the ring moves enough that it's way off-center to the lens, in fact causing it to rest against the lens barrel...not something I want. (An important aspect to a ringflash's look of not casting visible shadows on the subject is that the light is centered and emitted equally from all sides of the lens. Move the light slightly to one side, above or below and shadows begin to be more visible.) But the real concern for me is that putting all that weight on the TTL connection might cause the plastic to snap, potentially sending the orbis and my speedlight to the floor unexpectedly. Even if you could get through a shoot without tilting at all (right), just moving around like a typical shooter does makes whole attachment wobble and could eventually give. If you are in a crowded environment, like a wedding reception or club event, just the right bump could spell disaster. This problem was a deal-breaker for me and my shooting style, and I ended up returning it straight away for a refund. If orbis can resolve this major issue without increasing the cost I would consider it again.