Every day I see another turntable recommendation...

@saulh no it is not a suspension at all. The magnetic field is compressed by the weight of the platter until it is almost as stiff as a solid thrust mechanism not to mention that the platter is still located by a solid spindle. 

@clearthinker, vibrations can pass through springs but only below the resonance frequency of the suspension. Springs are mechanical low pass filters. The suspension on my Sota is set at 2 Hz with a very high Q so by 8 Hz everything is blocked. No mechanical vibration above 8 Hz gets to the sub chassis. Since the sub chassis is entirely enclosed by the plinth and dust cover much less airborne vibration gets to it. 

MASS DOES NOTHING TO ISOLATE A TURNTABLE FROM MECHANICAL VIBRATION. I will say this until I am blue in the face. It does help with airborne vibration but not mechanical vibration. This is the vibration that is passed on to the turntable through whatever it is sitting on. Some people have called it "room Rumble" as it occurs at very low frequencies right about where tonearm resonance hits which only serves to amplify the rumble. Foot fall problems are "room rumble" generated by walking. Room Rumble is generated by anything and everything that is going on in the environment from the cement truck running down the street to various house mechanicals turning themselves on and off. Mass does not protect you from this and in the minds of some (Rega) can make things worse. Sound waves travel through the ground just like through air. When they get severe enough you get an earthquake. There is a constant din going on in the background it is just below the level and frequency our own senses can detect but not the cartridge, it feels everything. That is what it is designed to do.

So, clearthinker, throw away your Kuzma Stabi XL DC AIR and get yourself a real turntable like a Sota, Basis, Avid or SME and enjoy listening to music without rumble. It will be an entirely new experience for you.

You have an excellent choice from the brands you have mentioned. But you really need to look at your overall budget for the turntable, arm and cartridge as you can expect to pay close to the price of the turntable itself for a really good arm and 50 percent of the price for a good cartridge - though you can economise somewhat on the latter. I agree that you should add Technics to your list if possible. The SL1200G is a very good baseline to compare against the other turntables you have mentioned.

@laoman @pindac Kuzna tables are wonderful! I've been using the Stabi S for a while and it's a great performer only thing is that it requires a solid, sturdy support. I've recently listened to the Stabi R which is in another league sound wise. Better focus and bass foundation to name 2 areas I hear where it betters the S. I'm saving up for this table myself. 

The Stabi R is great. However it is beyond the budget of the op. Stabi S is an excellent compromise.

"So, clearthinker, throw away your Kuzma Stabi XL DC AIR and get yourself a real turntable like a Sota, Basis, Avid or SME and enjoy listening to music without rumble. It will be an entirely new experience for you." This is such a funny comment; one can only assume the poster is attempting a new career as a comedian.

@mijostyn   I have had plenty of suspended turntables, for many years from the late 70s a Linn that I was forever having to re-tune so that the springs bounce evenly.  Then a Simon Yorke Zarathustra a massy design in which the springs were like car valve springs.  That worked better.  You may find it interesting that after that Simon stopped making suspended TTs, with the S7 that I used for a long time.  You may recall this was Michael Fremer's reference for some eight years before he moved out of my league into $six figures TTs.  I now run his S10, again solid, on which I hear no noise in an unmodulated groove.

You say vibration can pass through a heavy mass.  This is true but only for large vibrations.  Your example of an earthquake (caused by seismic movements, not by vibrations), is extreme.  Yes an earthquake may spoil your listening.  It may also bring your house down around you.

Small intensity vibrations of the type we are talking about do not pass through large masses.  To pass through such objects the soundwaves must move it = vibrate it. They cannot do that because they are not sufficiently intense = have the power.

I do not hear footfall seated as I am on a concrete slab covered with carpet.

But there is no need to create problems by having a suspended wooden floor in your listening room.

 frequency our own senses can detect but not the cartridge, it feels everything. That is what it is designed to do.

So, clearthinker, throw away your Kuzma Stabi XL DC AIR and get yourself a real turntable like a Sota, Basis, Avid or SME and enjoy listening to music without rumble. It will be an entirely new experience for you.