I recently put on fresh Magic Marys in Super Gravity casing. I'm using the purple Ultra Soft compound both front and rear in 29x2.35 (with cushcore on both ends). They're definitely heavier and slower to climb but the grip and damp / comfortable ride are mind boggling. While it takes more energy to move them, the extra grip does help with those steep tricky climbs this time of year. I will definitely switch to a faster rolling rear tire when the days (and rides) start to get longer in April / May. But for a winter slip 'n slide season dedicated setup this is the most sure-footed combo I've tried to date. FWIW my winter rides are mainly Fromme and Seymour.
Also, this tire combo can be had for dirt cheap if you're willing to order from overseas and wait a couple weeks.