I was looking for a replacement for my Canon 90ex which i thought was trashed, and came across the Bolt 310. This appears to be the only compact (except for the ultra compact and ultra low power 90ex) which can be used as a remote optical trigger on Canon - very useful on my 5DIV and other flashless Canons. Bolt also makes versions compatible with most other systems.
The 310 is the same weight and slightly bulkier than the Canon 270ex and only cost $100. In addition to the remote trigger (which can control multiple flashes and groups with ratioing), it will slave, has modelling/focus assist LEDs, articulates 90 degrees up and L-R, and has a battery indicator (which doesn't give very useful information with my eneloops). A diffuser is included.
Not quite as robustly constructed as the Canon, but should be fine if not abused too much. Controls a bit fiddly, but so is every other flash. Not yet sure about the battery life - the leds will shorten life also. But carrying another 2 or 4 AAs is not a big deal for occasional use.
Actual output is about the same as the 270ex. Using higher ISO with a reasonably low noise camera it produces a very useful amount of light even with the diffuser and a wide angle lens.
I will probably get the most use out of it in a 2-flash cordless macro configuration with the 270ex triggered by 90ex. The three flashes and batteries weigh a bit less than the Canon macro flash. The 90ex as a trigger won't ration but an extra diffuser layer and distance adjustment will usually work (using another bolt as trigger would allow ratioing and equal the weight of the Canon Macro) and getting rid of the cords is awfully nice for a carried and mostly hand-held rig. It (or the 270ex) is a very useful off-camera fill with the 90ex as a trigger.
PS If you only need a simple trigger and/or low powered on-camera fill,for your flashless/triggerless camera, overstock.com still has new 90exs for $100, and the 90ex diffusers (generally necessary to trigger flashes mounted on camera brackets) are still available.
