So I just had a chance to a-b-c my ZX300 with a Cowon Plenue R and a Questyle QP2R. The Questyle rocked my DSD files better than any other player I've tried-- for the first time I actually felt I could hear a significant difference. The Plenue didn't sound so good out of the box but improved immensely once I applied JetEffect. With all my flac files though, the difference was less obvious. On the whole all 3 sounded amazing and I struggled to hear a discernible difference between them. The ZX300 is easily my favorite player of the 3 for its battery life, portability and that certain sexy "je ne sais quoi" that Sony puts into its devices. I'm starting to believe that significant differences in sound quality among DAPs-- at least in regards to easy-to-drive IEMs like the Solaris-- is largely an illusion.