I'm finding the draw to be rather excessive - about 3 times what I saw with the Dragonfly on my 11" MBA, about 7-8% DF vs. what is over 25% with the ME. If I let my computer sit idle (running 95% free load in the background) and drop my backlight to 1 notch at 100% power, I get a 6:30 estimate after 5 minutes. If I add the ME in and play with volume slider at 50% for 5 minutes it settles about 4:20. Not terribly scientific but it should shed some light.
It's not hot by any means, but it does get a bit warm to the touch. I'd say based on this I'll be keeping it as it's pretty damn impressive, but I probably will reserve my DF for times when I'm not by a plug or just for quick coding sessions when I'm out and about - a 4:20 idle with minimal brightness is probably a realistic 2.5 hours while working.