Surprise attack, no prep.
DC: Superman, Captain Marvel, Captain Atom, Power Girl, Doomsday
MU: Hulk, Ultron, Juggernaut, Wonder Man, Sentry, Blue Marvel
all of the above survive, except maybe Wonder Man, who will come back from the dead as always. He probably survives though, but would be KO'd. Depending on the story, any of the others could be KO'd or badly hurt, or survive with no visible damage though.
This is because the DS usually hits one spot and it blows up the planet. Were the blast from the DS to hit them directly, WM certainly dies, and some of the others may be KO'd, killed, etc. by it.
Guys like BRB and Stardust were shattering planetoids with each other as part of their battle, this would be no more impact than that IMO