Suspensions on turntable...really effective?

I've used SOTA turntables (Sapphire Deluxe, then Cosmos IV) and have seen how they really isolated the playing from footfalls, etc. in a "medium" bouncy wooden floor setting.  I now have my Cosmos sitting on a Herzan active vibration cancelling base (yes, the type used to isolate scanning electron microscopes), and it just transforms the table into a much more neutral device and improves the detail retrieval.  The Minus K product mentioned above is also excellent for this.

+1 for Sounds of Silence. A Vibraplane will make a positive difference in any system. Alternatives are Minus K, or at a much higher price Herzan.

Steve at Sounds of Silence is great to deal with.

I use a "vintage" Linn Basik (Akito) with no suspension to speak of except the large rubber hollow feet it sits on (the turntable is on a light but stable little table of its own, as per the Linn instructions!). I recently obtained a second REL sub and it's about 4 feet from the turntable, all on a classic potentially bouncy wood floor. The result is zero footfall disturbance, when I touch the side of the turntable when blasting something no vibration is getting through (at least that I can feel by touch)…and the damn table sounds great and plays beautifully. I keep threatening to replace this table but it works so well I can't get rid of it.

I think the issue is, really effective against what? For example, a Linn, although spring-mounted, is terrible with footfalls, while a Basis, also spring mounted, is much better.  There are many theories as to how to design a tt.  Some say that spring-mounted tables are always in a state of oscillation and that a heavy plinth is the way to go.  So the short answer is - I don't think you can generalize about these things.  Each table has to be judged for its own merits and you shouldn't be shopping for a tt based on whether it is suspended or not.  There are just too many factors that contribute to the sound.