Who would you want?
Fella1,
fella2,
fella3,
fella4,
fella5,
fella6. I think all of them are better than the C that you typically find in free agency, but like anything else, if you don't have one of these guys on your team or in your farm, you're stuck with what's out there in free agency. I know that PC matters, but I won't run a 600 OPS guy out there just to get those 80+ defensive ratings behind the plate.
I recently traded away an older Ditr C in a World. He was the type of C mentioned above -- could hit decently and had defensive ratings in the 75 to 93 range, but could only play 50 percentof the time.. I traded him at the beginning of the season and by the end of the season there was a noticeable difference in the overall performance of my pitching staff. All the other defensive players on the team remained the same, but I had a below defensive rec C behind the plate for the entire season.
I also did the opposite in a separate World. I had a big time hitting C that wasn't terrible defensively, but I put him at DH or RF for the season and used my C that was much better as a pitch caller and it made a significant difference in how well my pitcher's performed.
I did this because I noticed one of my competitors in a World consistently used defensive C's and he consistently has pitchers that have only average pitching ratings, but somehow perform better than I expect. We both run defense first teams at the SS, 2b, CF positions, but he always runs a good defensive C and he seems to always have better team pitching peripherals than my teams despite having inferior overall pitching ratings.
As mentioned above by many users, there is usually a trade off. You need to decide if you prefer higher performance in your lineup or on your staff. For me, id prefer higher performance on my staff during the season and higher performance in the lineup during the playoffs.