I love Pak-Lites. We have many of them. (I'm only talking about the Originals and Supers, NOT THE BASICS)
They come in a bazillion LED colors and combinations of colors within one light and their runtime is fabulous. They are also 9V vampires.
The package is so small and discrete that few are hip enough to steal them in the workplace. Theatre techies love them.
Mrs Umbra and I have done many, many things with them, too numerous to list here. One example would be to mount a strip of Velcro on one that then may be completely hidden by sticking it to the underside of a table for emergency use by staff in case of a power failure in a theatre packed with people.
These are great lights which I have personally used extensively during the greatest natural disaster in modern North American history and also gifted to numerous greatful techies.
I have a Pak-Lite with cyan LEDs by my bed that is running off a used 9V battery pulled from a body mic years and years and years ago after a performance. The "use by" date on the cell is 2008. Its putting out about 7.5V. I tail stand it on the table so it won't hurt the light if it leaks (although my alkalines almost never leak). In my experience Pak-Lites will drain a battery pulled from a smoke detector or other device to the point where about 40% of them will terminate by blowing some of the cells out through the bottom with a pop. We have boxes of pulled 9V cells that are not leaking that are waiting their turn in a Pak-Lite.
I have never bought a battery for use in a Pak-Lite.
For us, they are well worth the price.
The closest I come to criticism would be to repeat my request for a "Covert" version, along the lines of what has been done with the Photon Freedom.