Our Prius gen 1 battery died last month at 312,000 km. I'm sure it's just a few dead cells that need replacing (see Youtube), worst case it will end up being a stationary battery. I'd happily buy another Prius but our deposit is down on a Tesla M3; that may never eventuate but we felt it was important to vote on desired tech with our wallet.
Note that Tesla uses Lithium (ion?) vs Prius' Nickle metal hydride so the longevity comparison isn't relevant. Also it's a lot easier to swap out the Tesla battery pack if there is ana issue (I think).
Random thought... how are all these deposits on the Tesla M3's affecting other EV/hybrid sales over the next 2 years? Will the hold off factor that I'm exhibiting be repeated by others? I suspect it will.