Yesterday I compared WSRP with two different RX. The first was RTLSDR (E4000 as direktsampler) and YAESU FRG-100. Both on same antenna. 12m wire on 9:1 unun.
The result is not that much different as I expected. Have a look at this animation. It shows stations from within Europe on 30m band.
|WPSR on 30m band|
Remeber: this is not a high end scientific research! Hower, it's interesting to see that WSPR is able to decode nearly same stations.
RTLSDR e4k (SDR#)
YAESU FRG-100 (on soundcard)