I'm kinda losing my hearing and I find none of the stock ringer tones on the five are loud enough for me to hear well. My old Droid gave me a choice of several tones of which I found one that really "shrieked" and I NEVER missed hearing that one! Anyone around me when it rang immediately covered their ears!
Wish it was available for the five! Is it possible to find louder ring tones somewhere? I'm not talking about songs..
And if the OP is asking about the "in-call" volume of a person calling in - yes - my iPhone5 is much louder than my Droid was for speech. This I am very thankful for! Sorry I can't compare it to the 4 since I never owned an iPhone before this five.. But I can vouch it's more than sufficient volume to hear a person very well.
A side note - when I place a call and turn on "speakerphone", it is very difficult to hear the outgoing ringer tones. But when the called party responds to the call that I can hear well. Yet, when not on speakerphone - I can hear the outgoing "ringer" tones with no problem. Not sure why the speakerphone kinda mutes those..