i want to know burn time, water tightness, switch function, cable connections, etc, etc.
Burn time: approx 3 hours. Never let mine completely die so can't give you a more specific answer.
Water tightness: I wouldn't go swimming with it, but if I recall correctly, someone on MTBR put one in a glass of water and turned it on. It worked. Battery is not waterproof, but you can dip it in pasti dip and make it waterproof.
Cable connections: On the lighthead, feels a little flimsy. However, I haven't tugged on it with any significant amount of force to try and pull it out of the solder. Connections between cables and battery fit pretty snug.
Switch funtion: Everything is on the light head, cycle through the functions a push at a time.
Conclusion: For the price, it does what I need it to do. Would I buy another one? Probably.