I bought one of these for about £10 delivered (PiFi DAC+ v2). I confess that the mention of the reasonable caps swung me towards this than other, equally cheap 5122 DACs.
It sounds okay, but I don't claim to have 'super ears'.
However, this review has prompted me to look a bit closer at the design, given the specified performance of the 5122.
Apart from the observations already mentioned (unnecessary DC-DC converter, ground side inductor), I'm discovering a whole bunch of poor design decisions.
So, those nice Wima caps (assuming they're genuine parts...)? Being used for PSU decoupling. A decent MLC would have been better, and allowed closer location to the chip. The Elna 2u2 electrolytics are used on the charge pump (and they're too far away from the associated pins). Again, MLC non-polarised would have been much more suitable (I've yet to determine if the Elnas are actually polarised correctly in-circuit...). The Wimas may be nice for audio, but for digital decoupling, they're wrong.
There's no signal side ground flooding, as recommended for crosstalk reduction (and general health...).
That 10u 'Nichicon'? Not well placed for good PSU decoupling, and, again, an SMD cap probably better suited.
The audio outs are run under the DAC, thus passing by the charge pump circuitry. Rotating the chip by 90 degrees would have allowed the analogue to be routed straight to the output R/C coupling. Admittedly the 5122 pinout is a bit questionable; one of the analogue outs is next to the charge-pump developed Vneg. I'd have surrounded them by Avdd/Agnd.
Decoupling of the various supplies is inaedquate, or too remote from the pins.
Still to finish tracing the mode selection, and work out if it's using a fixed h/w config, or supports I2C or SPI config. The device is pretty configurable in terms of upsampling/filtering; looks like the filter selection Amir tested was one of the more basic filters, as there are high attenuation filters available that knock the stop band down much more than the results presented here.
It's almost tempted me to fire up my long unused D/A design skills, and knock up a design 'done properly'...