Hello Geode,
If you search on HyperLuxV you will find my comments on it.
In short, I like it a lot. I don't have an L5, so I can not comment on that.
When I am fooling around the house, I run 2 X R-CR123's in it with a longer tail spring. It works quite well, but the run time is reduced. Around the house I don't care. Please note that it is not recommended to run unprotected rechargeable 123's in multi cell lights.
The head gets hot during extended runs inside, but outside I have not noticed that as much. I have used it kayaking and can say that it is extremely water resistant.
Tom