^ Tires of two different sub-genres best suited to two different sets of tasks.
Although the Tire Rack surveys are a resource I do use in my shopping, I use it very, very selectively. I've written about my reasons for this in the past:
Finally, a word on consumer level "surveys" and the like. Yes, they're of-value, but take a closer look. Look at the entries for the Michelin X-Ice Xi2. This tire was a top-ranked tire, at times, over the course of the last cycle (as, currently, it's all about the Xi3 ). Most people rank it very highly, right? Now start looking at the dates of the written reviews by these same consumers. Start rolling back the date, towards 2008, when the tires first came to-market. What do you notice? Strange, right? that the consumers who wrote about the tires then seem to be split between those who rave about the tire and just as much who rant that the Xi2s were "the worst tires they've ever had," right? Now fast-forward a little, one winter's worth, when the various known testing authorities have tested the then-new Xi2 and have put out their findings: that this tire was now the tire to beat in that category. What do you notice, now? That magically, virtually *ALL* the reviews are positive, no? Why did this phenomenon occur? it's because you can't tell what the experiences of the masses happens to be: how do you know that the results you're relying on are true? how many sets of winter tires has that person had experience with? how experienced winter drivers are they? etc. and so on. Yes, such a survey is a good resource - but use it for what it is.
To me, the the Altimax Arctics are not in the same performance category (in that it is a "studdable winter") as any of the Bridgestone Blizzak line tires ("Studless Ice & Snow" and "Performance Winter" categories) available here in North America, and thus should not be cross-compared. The Altimax Arctics are a good winter tire choice in their own right, and offer extremely good performance-for-the-buck, but this is a comparison that would raise more questions than supply answers, and the end result would depend more on the usage the tire sees rather than its own performance merits or shortcomings.
Between 215 and 225, you're not going to really be able to tell that much difference in terms of performance when it comes to being in the wintry stuff. As a Tire Rack representative once expressed on NASIOC, unless your last name is Andretti, Schumacher or Rahal, it's an academic difference you're not likely going to feel. A "two-width" jump, going from 225 to 205, for example, is something that most drivers can feel, however. But as for the 225 -vs- 215 debate? simply being at non-optimal tire pressures will have you off just as much - if not more - so it's really not worth worrying that much about.
As I've written before, "too skinny" does have its limits - remember that while we are talking about winter tires, we are still talking about tires that are being driven in the real world: that roadway may not always be buried under 16 inches of fresh powder that's sitting on top of hardpack - clear and dry roadways are a consideration that's very real in most cities, and for most drivers, the winter set must also bridge into the warmer transitional seasons. How many enthusiasts in this community - or any other - do you know of that runs or have run three sets of tires: one for the warmer months, one for the transitional seasons, and another for the deep winter months?. Not all conditions can be met with the ice-racing/rally ideal of specified "thin," spiked tire.
However, why the same aspect-ratio? you're losing about 2-tenths of an inch on the sidewall...there's a bit of play with the speedo - not that bad - but you'll lose that bit in ground clearance, too, and while the Forester isn't hurting in that respect, it's still a "?"
The WS70 is really putting up some impressive performance this year, and definitely would be in my list of contenders if I were shopping for "Studless Ice & Snow" tires for this season.
Your mileage needs to come into the equation, though, when talking about the Bridgestone "Studless Ice & Snow" tires, as their proprietary ultra-traction-in-the-wintry-stuff outer layer only goes down to about half tread-depth. If you're a high-mileage user, this may prove to be less than idea, as by the mid-way point, you'd be suffering the double-whammy of losing both tread depth as well as that wonder-compound.
That all said, what's more/most important is how you plan to use your tires. That's what will lead you through the very first decision that you must make: what sub-genre of "winter tire" (it's no longer called "snow tires," as there are sub-genre tires that perform better/best under specific conditions). Ice as well as roadway use legality comprise the first big split point in the decision tree, and will govern whether you want studded winter tires or "Studless Ice & Snow" tires. From there, you need to rank what your desires and needs are -
Do you need traction through deep powder because you live in a more remote area? Or do you value more a tire's resistance to "slush planing" because your roadways are almost always treated, but not necessarily plowed in a timely manner? Or do you desire better resistance to hydroplaning because your winter is just as wet as it is cold, or your area is both well-plowed and well-treated...but that snow just sits off to the side of the road and make rather large puddles that doesn't go away for days because the storm drain is frozen over by those same piles? Or do you need better clear-roads performance, because most of the time, your winters are just dry and cold?
Winter tires, in their current form, are always a compromise - there's no one magical do-it-all, no matter what less-well-executed testing/comparisons, or marketing, would have you believe. :wink: Look at some of our more recent threads : http://www.subaruforester.org/vbulletin/f72/winter-tire-recomendation-2-5x-touring-209290/