Music Server Recommendations

I'm looking for a new music server.   Sonos and Casatunes both look promising, do any of you have experience with either of these?  I would like to hear any other suggestions as well.

Hi,
may be I'm misunderstanding, but what exactly do you mean with "music server" ?
Right now I use a NAS for simple storage server and a couple of Minix U1 running Kodi as client players in different rooms...

Ciao

Is it still actual?
Recommend NuVo (Legrand) MP4SE. Or Autonomic Mirage Autonomic Mirage Audio System

Sonos if far better with not comparable price