I ride all terrains in hard boots.
Once I rode also with soft boots but now only hard but with different softened boots.
In freeride and powder, with all-mountain boards, longboards or swallowtails, I ride with UPZ rc8 with red tongues and DGSS spring system (green springs); I've cut the small tongue inside (in the rear of the shell) to have much more range of flex: amazing!
In other conditions, I ride with UPZ rc8 with standard black tongues and DGSS spring system (green springs).
With the DGSS spring system for UPZ I have a smoother flex and confort but at the same time trasmissivity.
Sometimes I ride also with AT light boots (La Sportiva Sideral) for backcountry with a Jones Hovercraft board.