Okay, I just tested out the Tekkeon and it is amazing. First of all, here was my informal test on the weight:
253.5 - Me on the scale in clothes
255.0 - Me holding the Tekkeon
258.0 - Me holding one of the eco-charges
My scale rounds to the 1/2 pound, but it still gives a rough idea that it weights around a 1/3 of what the eco-charge weighs.
You use the same button to change the voltage while it's on and check how full it is when it's off. The usb out is HUGE for me. I tested it both with the MT2496 and my iPhone. I am now going to tape Phish next Friday to test it out and also test out the firmware update I did on the MT2496. I'll give an update on what % of it is used powering both for a full show.