Thomas from the SWLing blog has been playing around with the recently announced SDRplay RSPdx and has come out with a comprehensive review of the unit. In the review he also provides some comparison videos on real signals between the RSPdx and other SDRs like the WinRadio Excalibur, and Airspy HF+ Discovery.
In the review Thomas notes that while having the advantage of being a wideband receiver, the predecessor to the SDRplay RSPdx (the SDRplay RSP2) was never able to compete with the similarly priced Airspy HF+ and Airspy HF+ Discovery units when it came to HF, MW and LW receiving performance.
But now with it's 0 to 2 MHz enhanced HDR mode activated, Thomas notes that the new RSPdx is majorly improved over the RSP2 in terms of sensitivity and selectivity on the medium wave bands. Thomas' tests also show substantial improvements in the shortwave bands.