I've been using these dazzling beauties for more than a year now and they're worth every single penny.
They may be small but they're easily the brightest bike lights I've seen in use, far better than the feeble ones that most cyclists seem to use. I've only seen one or two other cyclists with bike lights comparable to these in brightness - and you've guessed it, when they drew closer I realised they were also using these Smart Lunars. They were noticeably brighter MUCH further away than other cyclists lights, even from a long way away.
Unlike some on here I've had absolutely no trouble with water seeping inside and stopping them from working, maybe because I always double check the seals are properly in place when I fit new batteries.
In short these things are brilliant. Any driver who claims they didn't see you when you've got these things flashing away is either blind or lying.