There are three tire review sources I typically look at when going to buy tires:
- Consumer Reports
- Tire Rack
- Tyre Reviews (YT channel)
And what I've noticed is that the top three or four rankings every year are very, very close to each other. Meaning all the top performers are "good enough" to be worthy of consideration.
CR rates them in back-to-back blind tests. So does TyreReviews.
TireRack uses customer surveys. The upside is that there are litereally hundreds of thousands of reviews. But ... it's just one customer's opinion of their tire choice and a survey; it does NOT reflect a customer who had all 7 tire brands and then rank-ordered them.
So ... it's Caveat Emptor when it comes to reading ratings from different sources.
Per CR, the Conti ranked 3rd while the GY ranked at 5th. Ironically, TireRack puts the GY at 2nd and Conti at 3rd. (I find that a bit dubious as they don't have any data yet on the GY, but they "expect" it to place there.) Another example, the Michelin IceX Snow is rated #2 by CR, but it's #4 in TireRack.
I'm sure both the Conti and GY are both good winter tires. The issues you ask about (lifespan and dry grip) are hard to discuss because nearly all companies don't give tread-life ratings on winter tires; that's because they have no idea about the winter conditions in any one specific use area. Winter could be very dry one year and then heavy snow the next winter, all the the same zip code area. Snow tires are very soft, and the tire company has no idea how easy or agressive you'll drive. You really have no practical idea to know if one is going to outlast the other under the same conditions. No one I can find (not CR, or online tire reviews) ever discusses the longevity of snow tires; it's simply a topic that's ignored. As for dry grip, that also is somewhat vague, but CR does rate them equal in dry braking (they don't rate dry handling).
I think the following three statements are accurate regarding winter tires:
- Any winter tire that places well in multiple rating systems (CR, TireRack, TyreReviews) is going to be a good performing tire for the desired application (if it places in the top there or four positions in three different ratings systems, it's probably a well-rounded very good tire)
- It's improbable you'll ever find a consensus on what's the "best" tire (any more than a best oil, or best filter ...)
- YMMV.