I recently upped from the S3.4 to the C4. I mean the C4s are a lot better no doubt about it. The sound is just such a bigger deal through them, though the S3.4 is still a great sounding speaker. There is certainly a house sound to the Dynaudio speakers, I also have the Audience 42. If you don't have to huge a room then I would go for the C2, but if you do have a huge room and bass is your thing and you don't want to use a sub or upgrade later then go for the S5.4. I think you will be happy either way. If you got to hear them side by side my guess is you would go for the C2.
