Thanks. I think I have read and watched every review online that there is.
Best I can tell, if there is anything negative about it's internals, its issues with the extractor, shock buffer and spring retainer - after a few thousand rounds. This is the opinion of those on the Ruger forum that have had theirs a while
Simple and cheap to upgrade with parts found here - they have very detailed videos on how to swap
https://www.mcarbo.com/ruger-pc-carbine-accessories.aspx