I bought a 900mAh T-rex kit a few weeks ago from sterling vapor. One of the batteries died on me after a week of use using regular atty's, not LR (same thing, charged it but will not turn on/blink or anything even though the charger shows green) I'm getting a replacement sent to me here soon but my second battery is another issue.
I ended up dropping the t-rex (about waist height ~ 3 feet) on the floor for the first time after 3 weeks of use. The switch was incredibly loose and would turn on constantly without me pressing it. Soooo I was pretty ticked with these things, took that one apart, and found the little microswitch on the board was broke and completely useless
I LOVE the look and feel of these PV's but within less than a month they're shot (The 2nd battery was admittedly my fault but I would expect better/longer endurance from an $80 PV). I've noticed everyone seems to be having issues so I'll use the replacement battery until it dies and stick with the eGo from then on. If they start making a more reliable unit I'll come back to it but it seems like these models are not great quality unfortunately.
P.S. The 900 mAh battery lasts the same amount of time as my 650 mAh eGo battery... Probably because of the draw from the light ring but I thought it was an interesting note for anyone who was comparing