I've had three Cree lights sets (T6) for three years, I used gaffer tape to seal the battery pack and they've been great. On the lowest setting they last several hours. The lights benefit from a fresnel lens in them which gives a much better spread of light.
I also have two other twin lights jobs, the battery pack for one came ready waterproofed. One is a Yingding, can't remember the make of the other and I've had these for a year.
Their beam pattern is a bit more throw it everywhere, so I use these sparingly on the road.
I like the Cree lights.
PS, the O ring mount isn't the best, so better to buy a separate mount for the lights, they are readily available.