I am a HUGE fan of the Cloud Player. I like my FTP server in many cases but I can't do FTP at work because of IT security. I never tried getting on my FTP server with my phone. Also, I have SSL security set up on my FTP server so I need to do special configuration to get it going, I can't just hop on any computer with internet and have access to my music like I can with Amazon.
My favorite thing is that I uploaded a bunch of 320kbps MP3s and they stream at 320kbps from the cloud - no compression. The only problem with that is that when I have spotty 3g connection on the Android, it has trouble keeping up, but on my work computer, there's no problem with that either.
Two thumbs up from me.