I has a chance to set the NEX-5 under the veranda last night and try the lightning trigger. It works alright but there are a few issues.
I set the camera in RAW mode ISO 800 and did 4s shots. It does seem sensitive enough to trigger although you do need a significant flash for it to pick it up. One issue I've had is that once it takes the shot and saves it (couple of seconds) if there's another flash then the trigger picks it up and sends the signal to the camera but the camera waits to finish what it's doing then shoots which is a bit stupid really

So you end up buffering
triggering commands.
Another small issue is the lag time between the trigger and the camera shutter. I'll have to do some more test see if the camera is not trying to do a focus or smile detection or other before confirming but it seemed to lag a fair bit at time.
Other than that it was fun. I'll have to try with my Pentax *istD. Maybe the response time is faster as it's a direct cable connection.
I have two shots here. No definite lightning, more like a
glow. And this one
before without lightning. Btw that's my beautiful dark skies in my backyard