I have owned a QRO HF-2500DX since 1997. I have never owned a
Command, but know many who do.

The QRO uses Russian GU74b/4cx800a tetrodes, whereas the Command uses
3cx800a7 triodes. The Russian tetrodes are Russian mil spec, and have
been in good supply at extremely low prices over the last 5-10 years
(though they seem to have gone up a bit lately) whereas the Command's
triodes are still pretty pricey. My impression is that the money
saved on the tubes has gone into a more robust power supply and band
switch in the QRO.

If I had it to do all over again, I would again go QRO.

Ray K1XV