I dont have much experience with Iron Cobras but the few times I've played them they were really good. As for the sleishman.. I've never heard of that brand actually! Also you should check out DW double pedals, they are very smooth and fast.
In agreement on th DW pedals. I used Iron Cobras for years. At the time, they were the best out there that I knew of, but they did frustrate me a bit. A little slow on the return and I felt like I was fighting the pedal. 1st time I played a DW5000 I was sold. Smooth as silk and lightening fast.