All-WEATHER(!) tires
 

In Quebec, winter tires (with the mountain and snowflake symbol http://www.snowtyres.com.au/wordpres...SE_450x300.jpg) are mandatory from December 15 to March 15; all-season tires are not allowed. I drive about 3000-3500 miles/year, 50/50 city/highway. I don't want to drive in summer on winter tires because it seems unsafe to me, in addition to being inefficient (high roll-resistance) and winter tires wear faster in summer.

Hankook released a new tire, the Hankook Optimo 4S, which it calls an all-WEATHER tire. This means it's legal in winter, and can be driven year round.
("Allows you to have only one set of tires year round - both a summer tire and RAC approved winter tire. Lower rolling resistance than winter tires helps to save fuel. Outperforms our best selling all-season tire on ice.")

This could save me about 400$ (I won't have to buy new LRR summer/all-season tires) which I could never recoup in gas savings (I spend 400$ on gas PER YEAR!)

Has anyone bought these?
Do you think those tires are safe year-round?
Do you think they'll kill my summer highway mileage?

Don't have those but Nokian also has some all weathers, WRG2. I got a used set and ran this winter seemed better that the all seasons I've used in the past.

Prius owners have had excellent results with the Michelin X-Ice Xi2. They are LRR so the gas mileage hit has been less than with other studless snow tires.

For an all-weather tire I would have to second the Nokian WR series tire. It is a cold weather tire that can handle summer wheras all-season tires do the opposite.