If you used the same cartridge and phono amp, I am wondering how much of a difference would you notice between a mid level turntable and a higher end turntable. I would think part of the difference would be less vibrations? Hence the reason I purchased a Isoacoustic zaZen vibration reduction table for my turntable.
I can't give any definitive answer to your question. Others here are more knowledgeable.
But FWIW:
I "upgraded" my turntable, but I also upgraded the arm and cartridge too. I had an old Micro Seiki DD-40 Turntable with an Ortofon MC 20 Cartridge, and the (apparently) well-regarded MA-505 Dynamic Balance Tonearm.
I thought it sounded excellent and I enjoyed going back and forth between playing my digital music and vinyl. The sound was definitely on the side of the "slightly romantic or nostalgic" - that sort of vinyl warmth, records had a fair amount of noise, there was a very slight "fuzz" to the tone relative to digital, and complex passages in a track tended to start sounding congested.
Being an audio-nut, I sold the Micro Seiki and bought a (second hand) Transrotor Fat Bob S turntable - an over-built thing from Germany's oldest turntable manufacturer (1971 to the present). I've supplied a photo.
It came with an Acoustic Solid arm and a Benz Micro Ebony L cartridge. The cartridge - something like $4,500 CAD when new! - was thrown in to the deal. How can I refuse?
I have no friggin' idea how any of these measure, so this opinion is worth what you paid for it.
But I sure had a "wow" reaction when I first started spinning my usual records. First the general background noise, the record "hiss" between tracks and in quiet parts - seemed to have significantly dropped down, to the point I barely noticed it. It felt like lots of my vinyl now sounded new. Second, the clarity was amazing. There was no "fuzz" to the sound (so long as the record wasn't in bad condition). The sense of resolution, of hearing the faintest details no matter how quiet, subjectively started to match listening to my ripped CDs. And the sound remained beautifully clean and clear no matter how many instruments were added to the mix. Basically...it was sort of like making my records get closer to my digital source, though still with a certain vinyl signature that I liked.
I continue to be amazed by the sound from records I buy. I was listening to an electronic album from the 80's last night and no matter how subtle or quiet a sound, or how faint a tiny pool of reverb on a distant synth note, it was just clear, clear, clear.
I also built an isolation platform for the bugger. Constrained layer damping and on spring-based pods. I have no idea if this affects sound quality - I presume it does not. However, it certainly helped mitigate significant structural born vibrations getting to the turntable, e.g. from my tall son who would sometimes skip a record just by stomping past the thing on our sprung wood floors. Now it doesn't flinch (mostly due to the springs).