<p>PackMom: I know you asked about Prius in snow. My '06 Honda Civic Hybrid is fine in the snow (6 months of the year here) but I use Nokian Hakkapeliitta studded tires. The summer tires are Ecopia: I replaced the original tires due to rocky road sidewall blowout. Noticed better mileage. As earlier poster noted, sometimes the better mileage isn’t worth it for what you pay to get there. But I’m happy and pleased with both sets of tires.
I was worried about the software upgrade but–knock on wood–my mileage is still nice, the engine stops at lights, and the assist seems to function normally.</p>