So I own Borderlands on both PC and 360 and I recently played the game through on 360 and the game felt noticeably easier, I'm no PC FPS slouch either . I even turned the aim-assist off and the game felt easier. The AI felt dumber and I even feel like I was dealing with less enemies. I even managed to attain over 10 Orange Quality weapons, I call them legendary weapons (World of Warcraft) opposed to the 1 I got in my playthrough on PC. 
On PC I played as Roland (Soldier) and on the 360 I played through as Lilith (Siren) though I don't really think it was a class thing to be honest. I barely used the Phasewalking ability compared to the Sentry Gun with the Soldier. 
The one thing I can say though that was easier on the PC was using the Runner but that's more or less a control thing. I could've changed the sensitivity I supposed.
I'm not sure if there is in fact any difference in these things between the two versions but my play through on the 360 sure felt like it.  
 
Has anyone experienced that with this game or any other game?

So I own Borderlands on both PC and 360 and I recently played the game through on 360 and the game felt noticeably easier, I'm no PC FPS slouch either . I even turned the aim-assist off and the game felt easier. The AI felt dumber and I even feel like I was dealing with less enemies. I even managed to attain over 10 Orange Quality weapons, I call them legendary weapons (World of Warcraft) opposed to the 1 I got in my playthrough on PC. 
On PC I played as Roland (Soldier) and on the 360 I played through as Lilith (Siren) though I don't really think it was a class thing to be honest. I barely used the Phasewalking ability compared to the Sentry Gun with the Soldier. 
The one thing I can say though that was easier on the PC was using the Runner but that's more or less a control thing. I could've changed the sensitivity I supposed.
I'm not sure if there is in fact any difference in these things between the two versions but my play through on the 360 sure felt like it.  
 
Has anyone experienced that with this game or any other game?

Even if you turn off "aim assist" off on a console game it will still have a certain amount of assist whether it be from bullet curving or sticky reticules.

I think it has more to do with the fact that you were already well versed in the game after playing through it on PC.
Plus Lilith with proper weapons is just simply more powerfull then Roland.

Aim assist. That's all.