I got it because it was bright and because it had an integral CSPC reflector... something I wish more light makers would do, given that the law requires both reflector and light, even though reflectors aren't nearly as useful as people would think.
Like all other Performance Bike branded lights, it's flimsy and doesn't hold up long-term. My bike toppled and it suddenly stopped working, mid ride. So I got it replaced, but I don't trust it. I toppled again and then it fell apart while I went over a bump, except this time I could just put it back together.
One nice feature is that it has two blink modes, one where it blinks all of the lights on and off, and the other where it switches between two sets of LEDs, although research suggests this mode is extraneous. It's brighter than the Cateye reflector light. I've never compared it to the PlanetBike Rack Blinky 5. It gets a reasonably long battery life out of two AAA batteries.
This is an example of why Performance Bike sucks. By the features, it's great. But it's just not reliable because they cheaped out in various areas. And since Nashbar and Performance are actually the same company, it's also sold as the Nashbar Brilliant Taillight. Furthermore, which has me suspecting that it's really just a cheap no-name brand Chinese design, I've even seen it at DealXTreme.
Given that it's still working and I've got a backup, it either stays on my under-seat wedge or on my rack trunk when I've got the rack trunk mounted.
I don't recommend you purchase it, or any other Performance Bike branded or Bike Nashbar branded lights.