How effective has it been for you? I know I get noticed. Nobody complained they couldn't see me, that's for sure.

How visible is it? Can it be seen by others during the day? Please describe. It is very bright. I don't usually run it during the day except when it's rainy, but it is the kind of light that would work in daylight. I prefer to rely on bright clothes more in daytime however.

How well does it hold it up? Seems fine. My boyfriend's fell off and broke though. But he didn't mount it using the mounting bracket - he just used the clip to clip it to a thin bag strap.

Does it get affected by rain? Seems to work ok. But on my bike it's quite shielded from the elements by the seat.

How often would I need to change the batteries? They last. I bought mine last fall, as far as I remember, and I didn't have to replace the batteries yet. It must've lasted me for at least a couple dozen hours (in the flash mode) and there is no noticeable decrease in brightness so far.

Where and/or how many places could it be mounted? Mine goes on the seatpost. It has a sort of a clip, so it can clip to belts and backpacks, but make sure it sits there securely - if it's mounted to something too thin, it will slip off.

What other information is there that I haven't asked about? If so, what is it? I think all you need to know is there. My recommendation is buy it. It's a hell of a good light.