You can look at my audiogram to get an idea of my hearing loss. My provider originally tried to fit me with 85 dB receivers. My loss at high frequencies on the right ear is beyond the fitment range of the 85 dB. Yet she fitted me with 85dB receivers anyway because she wanted to see if she could avoid doing custom molds for me which is a more expensive option.
Well, I got saturated distortion on my right ear on the high frequencies right away and unless she reduces amplification in those high frequencies, the distortion exists.
I eventually went for 105dB receivers with custom molds and the saturated distortion on the right ear was diminished without having to cut down on high frequencies amplification. But for louder sounds, sometimes it was still there, which was to be expected because amplification for very loud sounds at very high frequencies can still reach the limit that the receivers can handle.
Long story short, the main disadvantages of higher power receivers are that they MAY require custom mold (100dB receiver for the OPN no longer requires custom molds however). They may cost more (up to 85dB receivers are standard with the price but 100dB and up are additional cost for the OPN for example). If your ear canal is too small, it can be an issue.
They also may have a higher harmonic distortion rating, but to me it should not be a significant enough of a factor.
The custom molds may make them look a lot more conspicuous because the custom mold can be seen more easily outside the ear while the domed receiver fits way inside the ear canal, virtually disappearing into your ear, leaving only the wire visible.
I gave up on trying to amplify my hearing at 6 and 8Khz because even the 105dB receivers aren’t able to let me hear sounds in that range due to my profound loss at those frequencies. All I hear at maximum amplification at those 2 frequencies is a low buzzing sound, presumably the distorted noise due to overdriving them.