I like the PC76 (the 1176 emulation) a lot, and use it all the time.. I often use it first in the chain as it's good at catching transients.
For example, I will use it first on a vocal, followed by the Ca-2a.
Now, the PC4K S-Type Channel is a different bag of bananas. It is an emulation of an SSL 4000 Channel compressor.
I struggled with this one for a while, but now use it far more. The metering on it is not that great for judging gain reduction, but if you use your ears instead it, works well.
I have used it on many different things, from jangly electric guitars, acoustic guitars, pianos. It has a certain sound that really works on some material, but I just found it harder to set up at first.
It is worth spending some time with - it is not as intuitive as some of the other PC compressors.
Now I love it.
Jonathan.