It is my daytime EDC, been that way for years. Has its disadvantages. Chinese battery problems. A few months ago I was told by Photon (or Laughing Rabbit) that they would replace my old, low performing battery I but chose to wait longer. the battery still works with less initial brightness and less capacity. I have a newer REX, purchased when the decision was made to discontinue the product.
Please consider taking the time to contact Photon and/or LRI about updating that type of light. Perhaps they could build a 1 LED unit with an increased capacity battery yet nearly the same size as the old REX.
The USB and photovoltaic chargers work on my REX's. just don't overcharge.