I bought this one off ebay for $36.
I think they are all made by the same company in China. I just bought it for a range/plinking toy on an M&P 22 compact. The mount is pretty weak. It's just a little plastic nub that locks it onto the rail, I don't expect it to last long.
The light is bright, the laser is really bright. I wouldn't trust it for anything other than some plinking fun. I won't get to the range until Thursday to try it, but I'm not really expecting much.
It also didn't fit the M&P compact(the light is too long) so I had to use a rail riser so it would clear enough of the trigger guard to fit on. Not a fault of the light but thought I'd mention it in case someone else bought it for a M&P 22 compact and wonders why it doesn't fit.
I think the best description I can give for it is it may be ok for plinking fun, I wouldn't expect anything more than that from it.
Batteries don't last long at all. The ones that came with it died pretty fast.