The hardware and UA sounded pretty similar, not sure of the free-ware. I would imagine the UA plugin has less noise and will never wear out. Most plugins you cant turn on "real time" so the hardware offers immediate tones and instead of the mouse, a turn of the knob...but then the software plug has the Save settings where the hardware has no recall other than a pen and paper.
For HR maybe not a big deal.
Id imagine if there was no EQ in the test, example- the straight preamp of the interface and the outboard without eq, the sound is even more similar.
Been running some tests on my gear and listening for noise floors and the usual mic comparisons, theres a ease of use factor that came in to play. ...basically less knobs = less confusion....my 73clone is preamp only, its a clone of the GreatRiver actually and compared to my ART TPSII, having less knobs can be good sometimes. The greatriver clone has Gain & Output, leds for both.
The ART TPS has a much more sound shaping capability with variable impedance, gain can go to distortion more (its designed for guitars and vocal) and the compressor built in is selectable etc.. but again with hardware theres no save function and I notice some amount of noise added with hardware probably not really noticeable if drums are going, but if the noise was added on 100 tracks it might sound like a freeway?
but in the end, preamp to preamp to preamp to cloudlifter to interface preamp ...in clean mode I cant hear much difference at all.
this test was mainly comparing EQ's so I can see that being all over the place, being a solo HR EQ'ing in the box later, as he did with this test makes sense. imo.
being picky I noticed the dudes room sound with the SM7b had a lot of drywall sound and the mic too far away adding to the room-drywall echo bedroom familiar sound.
overall though the whole youtube video was done really well, but maybe getting a different microphone he wouldnt need to EQ so much?