Destructo Disc vs Spirit Bomb

All things being equal, what's the better attack?

Who hasn't thought "why didn't they just use solar flare/a distraction and cut them in half?" Yeah, it's slow, but so's a genkai dama, and somehow Goku always manages to connect with that thing (Seriously, it's the size of a moon. Should be easy to run in the opposite direction of a giant glowing ball of death..)

Like every kind of attacks, what's better is situational.

Well, Freeza's own kienzan did cut him up, while the genkai dama failed.

Personally, I think Krillin's attack was subject to pretty heavy PIS. If you can find the time to charge a slow moving super attack like the kikoho, you "should" be able to work in an insta kill disc of death with good teamwork and liberal distractions..

The disc is more practical I think and only became useless when the opponents could heal at a ridiculous rate. It take much less time to ready the disc than the bomb.

Disc is better: Faster, tracks, can be spammed, never fails to damage (afaik) & isn't dependent on outside energies

As someone said, it's really situational. The disc cut Super Buu in half, but basically did nothing to stop him, other than stop Buu from using a single attack.

But the spirit bomb ended up killing Buu easily, once Goku was at full power.

And then with Frieza, the disk ended up being the death of him, even though he tanked a spirit bomb.

It just depends on the enemy.