I agree the EV mode is next to useless, the slightest hill or any speed over 10mph usually kicks it off for me. I mostly use it to force the ICE off while sitting in traffic (rare) or in the school pickup line for my son (regularly).
Remember the Chimerical competion between The 2010 Prius and the 2010 Insight? The Build up before release of the 2 automobiles. I always felt Toyota's driving "modes" were at least inpart a response to Honda's "Green" mode. Again Toyota's 3 modes..plus "standard" trumped Honda's Green Button. I can't comment on how useful they would be long term with ownership. But judging from posts seems a significant amount of owners do like Power Mode....