can you explain how QSX is different from the other SDRs being mentioned (ADALM-PLUTO, HackRF One, etc)? Is it just more transmit power than those other SDRs? I feel like i'm missing something.
The other difference is interface. The QSX, and other SDR-based transceivers, work like other regular transceivers. They have USB port for computer control and sound card output. Some newer radios provide I-Q input and output which can be used for more advanced modes. But the bandwidth is limited compared to the SDRs which can monitor an entire band.
The SDR sure has utility but that comes at a compromise. I've done some professional RF stuff in the past and 99% of the problems are solved with very simple and way more precise gear compared to an SDR.
Have a look at http://websdr.org and have a play around with SDRs and then go look at a video for a Yaesu or Icom "rig" and see the difference in the usability. The QSX is more the Yaesu or Icom end of things.
If you can't afford it, go for the QSX! I may replace my commercial rig with one if it's any good.