Townsend seismic sink or Clearaudio Magnetic

Anyone have experience of Townsend seismic sink platforms vs. the clearaudio magnetic supports for non suspended tts?
Views or more info appreciated.
Don't know if you mean the individual platforms or the large unit Townshend subsequently marketed. I don't know anything about the latter. If you mean the old Seismic Sink platforms for individual components, however, I had no end of trouble with them. Something usually went wrong so they wouldn't reinflate, it became almost impossible to level them, etc. I wound up throwing out 3 or 4 and giving the rest away because I wouldn't dream of taking anyone's money for them. Don't know the Clearaudios, but I'm very pleased with the Signal Guard II platforms I replaced the Townshends with.
I've had a Seismic Sink for about 6 years and never had a problem with it. Originally I had it under a sprung TT and it was a winner. One note after installing it I never looked back. Then I moved, and in the new installation I found it made only a slight difference compared to putting the LP12 directly on the rack, and that difference was perhaps not an improvement. I've heard it said that sprung tables should be mounted on rigid platforms or they will lose pace and timing. Perhaps the opposite is also true. But I also know there are many VPI owners who swear by Bright Star sand boxes. My advice is to try to determine the type of isolation (air, sand, cones, carbon, multi-element) before getting into which brand, but I think the Sink is a good product and a good value. If you buy one and don't like it for the TT, I'll bet you will find another component that loves it. DVD players, for example, are transformed by pneumatic isolation! I ended up with a Bright Star sand box under the LP12 (major hit) and after moving the Sink around my system found it best under my preamp, as it slowed down and over-mellowed my cdp.
I owned a couple of Sinks, they were a pain in the... you have to keep checking them for level and pumping them up every two weeks or so. I was fortunate I bought my Sinks used and was able to sell them for what I paid for them, good ridance. I found the Brightstar boxes much easier, cheaper, and have helped with my tuner and CDP. An alternative worth considering is the Cambridge Audio K500 Isomagic platform, available from Audio Advsior for $100. Finally, change the stock feet on your gear. I really like what the EAR feet do for my stuff.