Let's start with one that I have and, paradoxically, use - the SL400i. This is supposed to be able to stream audio from any uPNP-type server on your network. Unfortunately, there are two issues with this: the first is that it can't handle WPA WiFi security, so you need an Ethernet connection to your network. The other is that it is incapable of dealing with any vaguely modern uPNP server - it detects them OK, but any attempt to interrogate the server results in a crashed SL400i. And, as per every other Streamium product everywhere, none of the internet-based features work anymore. So it's junk.
However, because it looks cool (and I got it free) I bought it a mains Ethernet extender and set up a really old uPNP server program which it can actually converse with. In fact, the only other device it can stream tunes from is the built-in uPNP server in a WAC700/7000/7500 because they are similarly ancient!
While it sounds nice, the effort expended in getting it to do anything useful means that you should not pay more than I did for one... the earlier SL300i doesn't even have good looks to mitigate its uselessness and should be recycled immediately.