[m21sniper]

I think Freddie had a little more range than Adam, but not a whole lot. Probably the same is true for Plant. I think he could probably sing anything either one of them sang and still make it sound good though. Perhaps not as good, but he is unquestionably a superstar talent. You may like freddie's tone/style a lot better, but range wise Adam is almost on par with the legendary Mr.Mercury.

I think the most direct and relevant comparison would be to Steven Tyler. Which is of course really saying something.