It's kind of a long article but very interesting. The primary focus is how a particular SDR based chip resulted in a massive increase in the FM DXing hobby because the chip outperforms capabilities of any other. It's all open source.
Meet the Hobbyists Behind Today’s Smartest Radios
Excerpts:
The TEF6686 chip
... As Verhoeven wrote, the chip’s use of DSP technology makes it highly sensitive, capable of pulling in weak signals, and highly selective, able to filter out adjacent-channel interference. It supports both FM and AM reception, as well as RDS decoding. ... ....
By summer, the first versions of these radios appeared on AliExpress, sparking the open-source FM DX community’s rapid growth. ... ...
Serious DXing requires an external outdoor antenna. As a result, he hadn’t invested much in portable radios.
“I considered the Eton Traveler III a very good radio until the TEF came along,” he said. ...
..the proliferation of SDRs over the past decade has drawn a younger contingent to FM DXing. The open-source TEF project has only reinforced this trend. ... ..
Farkaš estimates that approximately 100,000 TEF6686 portables have been sold on AliExpress.
The “silver-metal” portable version is the model most DXers own, which is available on both AliExpress and Amazon.
On AliExpress, it is listed for $70 at this writing, but prices are subject to frequent fluctuations.
"The TEF’s performance is exactly as others have stated: unmatched sensitivity and selectivity, up there with any “conventional” tuner I’ve used. The portables are delicate, however, and chances are that you will break the whip antenna that comes with the radio."