here’s what I have tested so far:
RPi B with HifiBerry - excellent sound quality, very easy to set up and natively supported by Volumio (simply set audio device to HifiBerry) - only thing here is that you have to solder an 8-pin header to the P5 connector on the RPi (no big deal though)
RPi B+ & 2B with HifiBerry+ - same results as for the normal HifiBerry, only difference here is that Volumio runs smoother because of the newer RPi model and you don’t have to solder anything.
RPi B+ & 2B with HifiBerry Amp+ - amplifier integrated, sou you can connect your speakers directly to the HifiBerry. If using a decent power supply (I am using 18V 3A from an old printer), sound quality is really impressive for such a small thing. Again very easy to run with Volumio, drviers included. A little more expensive that the DAC only solutions from HifiBerry, but depending on your needs, this could be a all-in-one solution.
Audiophonics DAC Sabre ES9023 I2S (works with all RPi models): again excellent sound quality, personal impression is that it sounds even a bit more dynamic and powerful than the HifiBerrys. Really cheap compared to the HifiBerrys, I would say you cannot get much more for just $20.
If you want to use your CuBox, a decent USB DAC might be interesting. I’ve ordered this one via Indiegogo: indiegogo.com/projects/zupe … e-anywhere - specs sound really good, but I haven’t received it yet, so I cannot say anything on the sound quality. But there are lots of other affordable USB DACs, check out the Behringer U-Controls for example.
I don’t think you have to spend $250,- to get a proper streaming device, especially if you already own the SBC. If I had that amount to spend, it would probably result in an additional amp and maybe even speakers…
Hope this helps a bit.