I mostly listen to classical orchestra work and piano (the lower registers of piano never sounded "great" on S1.4)
The S1.4 is an amazing speaker for it's price, in fact for me, it is hard to find a better one within that price. It's shortcomings are evident when listening to acoustic instruments like piano, violins and specially cellos. The tone and harmonics are Somehow lacking and much to be desired. I still own and kept the 1.4s but have moved to the C1s for my main listening and I am quite pleased with the presentation which IMO, is much closer to the real sound by a considerable margin. I've also listened to the Harbeth SHL-5 which is an excellent speaker but the C1s presented a more convincing live presence for me. Other speakers to consider are from Verity Audio Parsifal, Vivid Audio, Sf Elipsa and Audio note. They are more expensive but so far those are the speakers which I felt is a step up to the C1s. Good luck!