When it's working properly, the TL-LD1000 is unarguably the BEST rear bicycle light available. I know because I've tried quite a few, including other Cateye models.
The light is essentially two very bright, independently controllable, 3-LED taillights in a single package. So, for example, I set the bottom triad of LEDs to blink and the upper triad to strobe back-and-forth. Both of the independently controllable lights are readily visible throughout a wide vertical and horizontal axis.
But note that I'm on my second TL-LD1000. And so I now find myself wondering if the light suffers from a fundamental design flaw.
The first TL-LD1000 I bought lasted a bit less than a year of regular use before it begin to spontaneously extinguish itself in response to normal road bumps. For a while a sharp slap would restore the light to operation, but the condition deteriorated: The light remained operational for a shorter period after each slap.
In response, I tried new batteries. I tried cleaning the battery contacts with a cotton swap and alcohol. I tried wrapping the batteries with some stretchy foam to help hold them tightly in place. None of those steps helped.
So after an email exchange with Cateye, I sent my malfunctioning light in and the company promptly replaced it with a new one.
I've used my second TL-LD1000 for just a bit less than a year, and now it too is spontaneously extinguishing itself and I'm once again slapping it to restore it to operation.
So, I would encourage other TL-LD1000 users to report on how reliably their light has worked and for how long.
As I said, it's an EXCELLENT tail light when it works. But from the standpoint of the light's long-term reliability, my experience has been zero-for-two...