The big advantage of the PBSF are the multiple mounting options. Most other solutions I have seen are most often only good for seatpost mounting. The PBSF comes with two mounts and you can also get a rack adapter.
Other than that there are now multiple PBSF more-or-less clones available which will serve the same purpose ... and the brighter Vetta light which has a separate battery pack and the red Ultrafire flashlight which is much brighter.
Agree - because I've got one on order from Wiggle. It's 1 watt vs PBSF's 1/2 watt. This will be my 5th rear light. Nothing wrong with the old ones -- I just keep coming across better ones I'd like to own.
I have a BB Mars 3.0 but the clip broke and the light went flying, but survived. I can't use the light without a clip, so it sits around. One hassle about the BB Mars, you need a tiny screwdriver to remove 3 screws to pop the lens cover off to get to the batteries.
I've used PBSF the last couple of years. One clips to back of a Bell helmet, one clips to the BPSF rack mount attachment (very secure). The PBSF clip is pretty beefy, and if something breaks, PB has good customer support (easy to contact also) and will replace it for no cost. I've had motorists tell me that I can be seen easily from half a mile back, so it seems to do the job. I use re-chargable batteries with PBSF. Just use a large coin to pop off the lens cover, and snap the cover back on. Quick and easy. Between October and March I always wear a reflective vest on my early morning and late afternoon commute rides, and that helps a lot also.
The PBSF is totally easy to mount and use. You can even clip it to your jersey neck back or rear pocket top seam.
Now, if you want a real driver-alert light, sunshine, fog or rain, day or night, look to your neighbors in New Hampshire: DiNotte. Yes, they're expensive. But people using PBSF's ask me, "What kind of light is that, I've never seen anything that bright!" Last week on a club ride on a busy road, I had it off. I had to get somewhere, so I broke away. Since I was alone without pack cover, I turned on the light when I was about a quarter mile ahead of the other riders. They said, "What the hell is that?" (I was later informed on the next ride.) You can't use flashing mode in pack riding because it's uncomfortably jarring to people's retinas.
Drivers roll down their windows, "That's a really nice light, I saw you a mile back," and they change lanes waay back and give you plenty of room: car honks by impatient cagers are rare. What DiNottes do is give drivers TIME to calculate avoidance, and smoothly pass you instead of frustratingly seeing you late, and getting boxed in, thus having to go at your speed until traffic opens up.