I am a big fan of the ACR 4F strobe. I carried one for years during SAR operations, using them fairly regularly, and they worked flawlessly to alert choppers and other rescuers to our location. I have also carried them when sea kayaking in a pocket of my PFD. They are great tools, but they are a bit specialized and somewhat heavy for most recreational trips.

A good many lights now incorporate a strobe function, but most of them are not as bright as the 4F. I have an EOS and its strobe is way better than nothing, but it doesn't appear to be in the same league as the 4F. Brighter is better. A good many of the bike units probably aren't bright enough,judging from what I see when out at night.