I haven't had any experience of that particular light, but increased "all-round" visibility is a double edged sword.
If you can see light over a wider area, then it has to be dimmer, because the same amount of energy is being distributed over a greater volume of space. Alternatively it'll just run for a shorter period of time at the same level of brightness, for that same reason.
It's listed as being powered by AAA rather than AA batteries, which is also typically a sign that it's dimmer, since AAAs obviously have a lower total power output than AAs, so you often find the smaller dimmer lights use AAA batteries.
It's quite possibly fine, but don't necessarily expect it to be a terribly bright light, because it probably isn't. The Lumi-ring sounds like it's essentially a "leaky" light guide, so it's probably not a bad idea to provide illumination over a wide angle. Some very bright lights directly to the rear, have relatively poor sideways visibility. That's one of the reasons I quite like the CatEye TL-LD-1100 lights, because of the ten LEDs, six point rearward, but two pairs point off sideways, so it has good visibility from that angle as well.
