The bow lights (which live where only an offshore racing bowman can survive, for a while) are the the only ones that have given me problems. That was due to the sealing of the wire entrances to the back of the light. I replaced the one the didn't work (plus the other one that was still working) This time I sealed it with enough silicone to make a 44D breast implant ;^). Still working five years later.

My grip with the Aqua Signal units is the current draw. It really isn't an issue for the running lights under motoring conditions. But the anchor light and the sailing lights bug me. The Lopo Lights are so elegant, so apparently reliable, and (unfortunately) so expensive. If you're going to an LED light for that application, I would go with them.