I've already got an MXDL SA-28 from KD and it's realy bright. I know there is no way the one from ebay is having 300 lumens, but it's quite similar looking to another one I've purchased at Foclaprice (http://www.focalprice.com/LF575B/C84_5W_Three_Modes_Capacity_Q5_Light_Bulb_Flashlight_Lamp_Torch_with_Clip_Black.html) and I would love to try it out.
Small Sun C84 is less bright but has wider beam (something in between SA-28 and Romisen RC-C6) and it takes quite less power from 18650, so it should last longer. I've made current a measurments in high mode with same battery at 4.18V and I've got:
MXDL SA-28 1.55A
Small Sun C84 0.73A
Quite a difference in a current, but not so much in a brightnes. They have also different led emmiters: SA-28 has XR-E EZ1000 and C84 has XR-E EZ900 looking. And SA-28 makes bigger spot when focusing at throw position.
Not all that many lights are capable of 300+ lumens. None of them are all that small. Here is the list of lights and dropins I have that are capable of 300+ lumens.
Not quite. We all know, the bigger the lens, the better the throw. So this one worth to be mentioned here: http://www.kaidomain.com/ProductDetails.aspx?ProductId=10718
It has a 28 mm lens. This makes a nice small square (about one third smaller than most other zoomies), but with higher intensity. The only bad, it runs on three AAA cells only. If it would come with a extension ring to run it with a 18650, it could be perfect. It has two modes (no blinkings) and build quality is good.
I would say: probably yes. At least I could accidently put SA-28 tail cap on one of the same diameter. It was some version of torch with red ring like this one: