:/ I've used an EVF on an old bridge camera (Fuji S5200), borrowed a Nikon V1, and been handed a few modern EVF Fujis. The new finders are good, but I doubt that a single battery is going to fare well for sports or event photography where one spends a lot of time looking through the viewfinder waiting for a particular moment. I've "started" (well, I guess I've been doing it for a few years) using live view on an SLR for focusing an 85 f/1.4 in low light because it *is* much better than trying to do that through a viewfinder (even with electronic rangefinder), but I definitely feel the battery drain, even though I focus once and then go back to regular "mirrored" shooting.
But you're right... I come from the split-prism era of viewfinders.
(Also, I thought EVFs, though smaller, still had similar power consumption to their large-sized LCD counterparts. Is this no longer true?)