We tried to get there from Kielder. Turned round as the snow kept getting deeper. There was still loads on top and didn’t look like anyone had been past Lonesome pine in a while as we were cutting fresh tracks.
Which ever pedal you pick you need to stick with it long enough to get used to it. I find the performance gains of spds to be marginal at best. I generally prefer to use flats as I like normal shoes (I can take several pairs if riding consecutive wet days). Normal shoes are also easier to walk in should you need to. I also prefer not being clipped in as I feel happier/confident pushing it on the downs.
Having said that I am at the faster end of the group I ride with so don’t need the marginal gains. When racing I’m always on spds. Ridden with both on and off for several years. Depends on what type of riding you are doing and with who.