At a street price of about USD 20 to USD 25, they are undoubtedly the most capable low-cost SDR hardware that can be bought. So now there is really no more excuse for anyone to not learn gnuradio. You don't have to buy a USRP, not even a FCDP or an OsmoSDR: A USD 20 device is all that's needed for receiving signals like GSM, GMR, DECT, TETRA, APCO25 and many others.