Well I have flown UA F, UA C, SQ Raffles and SQ f.
UA C is just not be compared - the seats are not lie flat, but as some people mentioned rather comfortable to sleep. Food and wine as well as entertainment system ( no AVOD) just plain lousy on UA compared to SQ. SQ C beats hand down UA C and even with regard to entertainment, food and wine UA F, seat wise the suite on UA F is extremely comfortable to sleep, I find that seat excellent, but then again SQ F again in my opinion is in another league compared to UA when you compare the overall product