You have likely never given it a really challenge like a very weak station next to a very strong one and then use all the features. For many listeners and what they do, your experience might be typical. Or compare the HF+ to any of the others using a YouLoop antenna (not the cheaper Chinese copy), one quickly sees the sensitivity difference. You can only compare using something hard to receive. I would expect the 8600 and duo to do well but my tests have the HF+ doing better. The dou should be better than the 8600 in dynamic range and I would give it 2nd place. The R8600 of curse does not need a PC but is a step down (yes, I know some will argue). I back shelved the R30 simply because I could always grab one of my 4 HF+ Discovery (or Airspy R2 for VHF/UHF) and do better.
Do you use your Airspy HF+ Discovery only with the small portable loop antennas, or something larger eg. on rooftop or between trees? Did you observe instances, when strong signals in vicinity can 'stun' the receiver?