anyone have any experience with MARS Coils-good or bad?

I have the 2 frequency coil that I bought for my Sorex Pro. I feel that it is a good performer and seems even a little more stable than the stock coil. Workmanship seems good also.

I've had the Mars Tiger coil for the Racer 2 for a while now, and it seems to be a good performer on both separation and depth so far - very light coils for the size.