The difference in the sound pressure between handgun rounds is like asking if you would rather be deaf as a stone or deaf as a rock.
Yes, there are measurable and theoretically large decibel differences between them. However, the "quietest" is loud enough to permanently damage your hearing with a single shot while the loudest is loud enough.... to permanently damage your hearing with a single shot.
Sure any handgun round has the potential to cause permanent damage, but that does not mean that some do not have the potential to cause more damage than others. You are basically saying the difference in decibel levels between pistol rounds is negligible, but the .357 round can be as loud as many long arms? I no longer carry or use a .357 for home defense after a single .357 round left me with permanent tinnitus in my left ear 2 years ago. The .357 is notoriously loud and much more punishing to the ears than say a 9mm or .45, and is just as loud as a 12g shotgun and several long arms. On the decibel scale the .357 is leaps and bounds ahead of other pistol rounds, and seeing as I have already done enough damage to my ears I would like to minimize the chance of further damage as much as possible. It is reasonable to assume that the higher something is on the decibel scale, the more potential it has to cause damage when compared to something of a lower decibel level. Note I said potential, because it is not written in stone that you fire Round A and you will suffer this much damage compared to Round B. But I still believe a higher decibel round increases the potential for how much damage it will cause.
As far as big and heavy vs fast and loud it depends on the caliber. In a 9mm HP I like the 124gr rounds vs the 148gr. In a .380 I prefer the heavier 102gr gold dots to the typical 90gr HP's, in .45 Colt or ACP I prefer heavy and slow to light and fast.