"Aguero is now coming up to his 32nd birthday and he's still banging in the goals left, right and centre," the Newcastle United legend said.
"I know he's playing in a magnificent team but 180-odd goals, 260 appearances and look what he's won also.
"I love both of them, Thierry was different. The role now as a forward has slightly changed.
"There's not so many centre-forwards now, it's a forward but the one constant is you have to score goals and both of them are not only great goalscorers but scorers of great goals."