I bought a set of Marathon Winters several years ago, and they worked extremely well on the rare icy conditions I got to try them on (including a couple of hundred metres of sheet ice).
However, they were a pain to ride on when it wasn't icy, so on the basis that I have a mountain bike, I bought a set of heavily discounted Ice Spikers to fit to that, so that in the absence of a prolonged freeze I could grab the best bike for the job on a day by day basis without faffing around swapping tyres.
The Ice Spikers are even slower rolling than the Marathon Winters, but the greater knobbliness means they're better on soft stuff (as last winter was so mild I've only been able to test them on mud, rather than actual snow). I anticipate similar performance on solid ice, and I expect that being wider should make them handle better on re-frozen slush.
For completeness, I've also tried a Marathon Winter on the back of an ICE trike. This gives you enough traction to get moving on ice, and normal tyres on the front wheels still give enough grip for steering purposes. Rear-wheel braking is underwhelming and front-wheel braking is non-existent, but it's only the confidence of not being able to fall off that enables you to discover that. 20" wheels on refrozen rutted slush are incredibly hard work, even if you have traction.
I dismounted to take this photo (the trodden slush had frozen solid overnight), and promptly fell on my arse; my boots had no grip at all:
That's the limit of what I'd consider sensible on a bicycle with Marathon Winters, not so much because it's solid ice, but because it's so lumpy. The equivalent in dried mud wouldn't be much fun without MTB tyres, either.