My boss had a set on his mini last winter and reckons they were great. I pondered but do so few miles it ain't worth it. Got a set of autosocks just in case.
'This changes power delivery to the wheels.'Does that help when your're braking?
Anne,yes, there is a benefit in the cold - summer rubber gets hard below 7degC, and starts to lose its performance. Its why plenty of Northern European countries mandate you run on winter tyres between Nov-Mar (approx), even Belgium, where they're not exactly a big snowfall country.
What I've experienced is that summer tyres are a lot less gripy when it is cold - in both wet and dry conditions. This can be a difference between 10 and 13 meter stopping trail (hitting, or stopping just in time). All 4 winter tyres do great difference on braking and cornering when it's below 10 degrees Centigrade.Expense is not too great - because when switching tyres they last about twice as long. Just get a spare set of wheels (rims) so you do not have to take tyres off to replace, just swap wheels - 30 minutes work. In my country it is mandatory to switch to winter tyres in November but I'd do it anyway.