I see. I am basing that comment on the assessment that the AT95 cartridge the RT81 comes with does offer better quality than the one the LP70X comes with (and part of the reason it is more expensive). Likewise the VM95 in the RT81+ is supposedly a further improvement if he wants to go up a few more dollars. There was some speculation about the construction of the Fluance with its heavier plinth construction and isolation feet also contributing though. I don't know how accurate that speculation is, but in an analog device like a turntable I can see that being a (small?) possible contributing factor.
Look at the other AT cartridges- many manufacturers make a few with different tips but the rest of the stylus can be the same- this allows stepping up in quality without changing the cartidge body.
The usual differences between turntables include:
- Speed accuracy
- Isolation from noise/rumble coming through the base from people walking and other impact sounds, or from the speaker(s) being too close and the base being too light and unable to dampen the sound. Mass prevents easy transmission of sound from the speakers, but not necessarily from underneath- damping feet and material in the bass help with this.
- Better tonearm- the design of the tonearm matters WRT how the stylus aligns with the groove and the angle changes as it moves from the outside of the LP to the middle. It's only 'correct' in two small areas- the rest of the time, it's not but the error is generally small enough that the effect is inaudible UNLESS there's a way to compare perfect alignment with the turntable in question.
- The mass of the platter- if the platter weighs almost nothing, it will be badly affected by sounds in the room. A heavy, rubber mat can help.