C Interactive titles are very sharp on most small to mid-size TV, I can't vouch for higher sized screen since my unit is just 32". Even if they are DVD5, they often include a plethora of features, rivaling R1 on those. Some are even DTS.
However, there had been reports of skipping or discs that become unplayable after a few views, but those have not been reported lately...
As I often said, if it plays perfectly, C Interactive titles are really bang-for-the buck. But for huge titles, that I want to future-proof (ie expect to watch again in 10 years), I often get the R1 version too...