MY UNPOPULAR OPINIONS!
- I really don't like Ritsu's voice. It's just... meh.
I think these could be considered unpopular, at least.
I partially feel the same.

Don't get me wrong, Ritsu's quality for an UTAU or freeware synth is pretty impressive with how clean it is,
Canon clearly knows how to make a clean vocal..Though it's been years since I've tuned Ritsu, so I might be not remembering well.
I don't like Kire voicebanks as I find the loudness to be disturbing, and Ritsu is partially responsible for the Kire voicebank genre.
Fans of Kire and Power/Solid style voices tend to be rather hard to understand, because some of them give off the idea of "loud yelling = good singer."
They put a lot of expectation whenever their character gets ported/upgraded,
Kasane Teto fans specifically tend to voice their complaints a lot, about SV Teto not being as loud by default,
even though:
1. She can be tuned and mixed to match
2. UTAU resampler's peakcompressor/normalization is where the power comes from,
3. Teto Sakebi's samples are so unnatural, that it seems like she was either too close to the mic, or they put audio effects on her besides the pitch shifting..
Sakebi could've been better.
The microphone they used is lacking, and I'd rather have the more natural singing of SV
than Oyamano Mano tearing her vocal cords trying to voice act as Sakebi,
or the mixer dealing with audio distortion by an artificially-tense vocal.
There are times where loudness is inappropriate for a song, such as those Ritsu covers of Palette by Yuyoyuppe.
That song is meant to be sung with a light falsetto voice if we take Luka's voice as example.
It's supposed to sound ethereal or angelic, the instrumental is the shouting part.
If we have everything be loud all the time, then the song will sound indescribably lesser.