Well see here comes the problem.
"strongest" is subjective. The way strength is perceived is only relevant within the parameters of the show that the character is in. For example Goku shooting giant explosive Ki waves at enemies quickly becomes impossible to accurately gauge the power of from the beginning to the end of the show the scale doesn't appear to slide that much "The only thing we have to go off of is the arbitrary power level system and who has beaten who, who is stronger than who." What I mean by this is the animation itself seems to be inconsistent. Here's a few examples.
Exhibit A:

Now if you will, please fast forward to 7:16 where Racoom spits out a blast and completely obliterates an island.

Exhibit B:

And at 1:12 where Raditz blows up several mountains.

Searching for dbz power levels reveals that Racoom was at a measly 40,000 and Raditz measured at a completely pathetic 1,200. Yet Raditz appears to emit a much more powerful attack than Racoom effortlessly. There's many examples of this, like Vegeta getting mad somewhere in the namek saga and appearing to crackle with power. The same trick they used on Gohan when he ascended to super saiyan 2.

And just for kicks, watch this one.
https://www.youtube.com/watch?v=saWJJcvwnawp
Good examples being 1:42 - 2:14.
With Goku's power level in super saiyan form being 15,000,000 when he does it for the very first time in the Frieza saga, Meta Cooler clocks in at 17,000,000.*which is funny considering he is easily wiping the floor with both super saiyan Vegeta and Goku. With their power levels combined they should be kicking the shit out of him*

My point is, we can't really tell whose stronger than who unless the show tells us by two options A:Animating it to show us. B:By having a character say so, get his ass kicked, etc. And since option A is out of the window from the get go, it becomes increasingly blurry and confusing without referring to the totally bogus power levels lists.

That said, I like to think of it as a characters strength is only relevant within the boundaries of their own show. Goku can't exist in a the cowboy bebop universe. So you shouldn't compare Goku to Spike Spiegel. Bebop that's a good one.


Since in this universe humans are depicted as normal *Easily disposed of with bullets*. It speaks to me worlds more that Spike not only survived that bullet, but also the long fall and somehow the drowning. Opposed to how many exploding rays of variously colored lasers Goku has taken. And not to mention how powerful his opponents hands must be, to tear through flesh and bone that easily *something that if done in Dragon Ball Z has almost no real effect on the viewer*
Though as a plot device of that show only Spikes brother Vicious can kill him, it's constantly established throughout the show.

Then again it's all subjective.