Yes, he is underrated.
He is not a tech Guitar Player but a grinder, a musician with feeling. He is definitely an awesome performer and that is part of Rock and Roll.
His style never tried to match Satriani, Blackmore, Eddie or other greats...no he has his own style and along with Brad Whitford i would say...untouched. What i love about Joe Perry is that he has managed to put a little bit of Jeff Beck in his playing...not a copy...but its the way he chooses to connect the notes. Listen real careful and you will see.
I have seen lots of Perry Performances...yes...a blues, rock axeman who chooses quick and killing solos and not the "never ending" solos.

Here is the first name Ive seen that actually fits the bill for the guitar slot. Pure American rock style guitarist. Blues licks and male angst. This is where American rock starts.

One of the most under rated axemen in history.Aerosmith is a great band to see live!

A great guitarist.