As I see Nokian WR mentioned - these are not "all season", but proper winter tyres (for central european conditions). They will, like any central european winter tyre, be inferior to nordic compound winter tyres in snow and ice performance but easily beat them on wet and dry tarmac. I guess that makes them much more all-seasonish than nordic winter tyres, but still, they will like any other winter tyre be rather awful to drive in summer. Winter compound and summer temperatures don't go well together. Heck, winter tyres are even inferior to summer tyres on dry roads at low temperatures!
But they are significantly better than summer tyres when you expect ice, slush or snow, which is why you will accept some performance decrease in the dry (when you expect winter conditions).
Yes, when facing the choice between driving winter tyres in summer or summer tyres in winter I'd probably go with winter tyres year round as the lesser evil of the two, (while significantly worse than summer tyres on dry roads, that is much more controllabe than summer tyres on winter roads...) but it's nothing I would recommend.
Use summer tyres in summer and winter tyres in winter. If you expect mostly plowed and salted roads, meaning bare tarmac with a bit of slush and only very few days of snow or ice, go with central european tyres. If you expect mor snow and ice or performance on these few days is of extreme importance (as your job depends on it or omething like that) go with nordic tyres, but expect significantly decreased performance on dry and wet roads.
Buying summer and winter tyres does not, as some have already said, cost more than buying one set of all season tyres. Say, for example, one set of all-seasons lasts you two years. Two sets of alle seasons last you four years.
No you buy one set of summer and one set of winter tyres. If your mileage dpes not change, your summer tyres shoul dlast four summers and your winter tyres four winters. So you use two sets of tires in these four years, just like with all-seasons. The only difference: 15 minutes of work in your driveway each spring and winter - and much better performace.
There is no true all season tyre and there can be no one. The requirements are too conflicting. With all season´tyres, you have three choices:
a) equally s..t both winter and summer,
b) decent in summer with very limited winter capabilities,
c) decent in winter but limited summer capacity.
Neither of which seems attractive to me, if I can also choose both great summer and great winter performance with summer and winter tyres at nearly the same cost...
