I heard both amps, with different speakers though. I listen mostly to Jazz, vocal and Pop. It was a hard decision to make. At the end, I went with the CS600. The headphone output is a plus. My Sennheiser HD650 sounded very good with it. The CS600 came with stock tubes Sovtek 6L6WGC which I didn't like. I replaced them with new reissue Mullard EL34 and I like it much better. The Mullard EL34 sounded less lively (with less extension on both ends) than 6L6WGC but it is smoother and the mid range is more pronounce and sweeter. I can live with it. I will try other tubes such as KT77, KT66, KT88, KT90, KT120 and 6CA7-Z (maybe this tubes is compatible, got to double check) in the future. I just noticed that the price for SED Winged C EL34 at thetubestore has increased again. It was $49.90 last month. Now it is $57.95. Probably I should get a quad now. Some say KT77 is better. Some say SED Winged C is better.