Looking back pre-DCnU and pre-crisis I always saw DC as having the most heavy hitters in terms of real powerhouses, at least when looking at characters who appeared reasonably regularly and were in team lineups.
DC had a lot of top-level super strong characters running around like Superman, Wonder Woman, Power Girl, Martian Manhunter, Captain Marvel, Black Adam, Supergirl etc. On top of vast strength they had incredible speed, flight, a high degree of invulnerability in most cases, and a host of other powers. Then there were a whole lot of exotic guys with crazy powers like Green Lantern, Firestorm, Doctor Fate, Flash, Captain Atom, and so on.
Marvel had a few high-end bricks like Hulk and Hercules. And Thor had limited flight and exotic powers as well. None of them were speedsters. Then there seemed to be a whole heap of strong guys like Thing, Colossus, Sub-Mariner, She-Hulk, Wonder-Man, Sasquatch etc - strong but not quite considered top level.
Most of the Marvel strong guys didn't have much else power-wise. And a lot of the other non-strength types were kind of mundane compared to DC. A lot of classic Avengers lineups seem kind of low powered when compared to classic JLA linueps.
Later on in Marvel Gladiator was introduced, Hulk went on to crazy levels, more and more Hyperions showed up, Sentry, Blue Marvel... now Marvel has a whole bunch of mainstream Superman types with strength, flight, eyebeams, speed. She-Hulk, Cage and others got big boosts. Feats started getting crazier. Mutants got completely out of control. The current Avengers lineup is probably the most powerful and diverse ever. The heavy hitters aren't as well established in most cases but they are close to DC these days.
I was more of a Marvel than DC reader (though I did follow some DC titles) because even though I saw DC as more powerful I preferred the stories at Marvel. These days Marvel has really upped the power levels and have kind of gone crazy. I actually don't follow any DC post-reboot and I've pretty much given up on Marvel's new direction as well.
Kind of rambling but that's it...