I'll second the Mapletree, however I must disclose that I have one currently for sale here. I found it to be more musical than the QS with a fuller sound stage. I used both on top of McIntosh amps. The QS with a MC 7270; and the Mapletree with the same MC7270 and a new MC402.
Sorry I don't know the other 2 brands.
Tony
Sorry I don't know the other 2 brands.
Tony