Best Isolation HRS? SRA? Zoethecus? Symposium?

To answer your question clearly: yes, an isolation device will make a big difference. Black Diamond Racing Cones give good bang for the buck. Symposium roller ball feet work a bit better, especially when you have the tungsten carbide balls, but they cost a lot more. (You pay the price for hard balls.) I haven't tried most of what the other guys are having.

I second Jtinn. Try also apex & formula shelf!!

For me, the choice wasn't even close. I opted for Silent Running Audio's Craz rack and Ohio Class XL+ isolation platforms, and haven't looked back. IMHO, there's nothing better on the market, and that includes Grand Prix Audio. The secret is that each platform, and each shelf on the rack, is designed specifically for the component it supports. Now that SRA is accepting trade-ins for old platforms, and offer new support pads for the rack shelves FREE OF CHARGE, it's no longer a monetary hassle when you change components. I could've bought any rack out there, and I chose SRA. It's a no-compromise solution--the best of the best, IMO.

I have three Critical Mass bases. Two, which I have owned for about 5 months, sit under Joule Rite Of Passage amps. The third is nearly 2 months old, used to isolate my preamp. I have seen no change in level. The product is aesthetically top-grade, and so far, the construction has proven to be as well.