Yeah, the question of receiver vs pre-pro has been asked a lot.
Facts - according to acutal measurements, they are both equivalent in terms of sound quality when DSPs, EQs, & Tones are bypassed.
So it really comes down to other factors, instead of performance.
Aesthetics & "bragging rights" are huge. For example, "I have a pure dedicated pre-pro and you have a receiver

".
But the question I want to know is, which types are more reliable?
Are pre-pros more reliable because they don't have that amp section?