AC/DC overall now. I'd give the edge to GnR during the Appetite/Live like a Suicide era...up until the UYI albums came out.
Then, the edge went back to AC/DC.
Now, since GnR technically doesn't even exist, AC/DC is obviously better.
Angus is a better guitarist than Slash. Just because AC/DC has been writing the same 3 songs over and over doesn't mean Angus doesn't have more chops.
Slash basically plays the same solo over and over anyway.
I'll give Bon Scott and Brian Johnson the edge over Axl for live performances. They sounded/sound about the same night in, night out...whereas Axl's voice is only good for about the first 3 nights of a tour, then he sounds like a frog.
Case in point: Someone show me where Axl EVER sang Sweet Child 'O Mine well live. Even on the live album he sucks singing that song.
Every singer gets a little hoarse during a tour, especially the screamers, but Axl's voice really sucks live, most of the time.
In the studio? I'll put Appetite up against Back in Black and call it the winner. But AC/DC has more albums, has been around longer, and has more GOOD solid songs than Guns.
The Use Your Illusion albums were a waste. There was enough material between the two to make one GOOD album. But there's too much filler in there for two legit albums.
This is what happens when Axl started getting control.
Now, he has complete control, and we see what's happened.....basically nothing for over 10 years, album-wise, and nobody left from the orignal Appetite lineup besides Axl.
So AC/DC gets the nod here, even though I liked Guns better when they were still together.