I've owned the 5i but never heard the CAT. The 5i is a great preamp. It was Stereophile Class A, if that means anything to you. Be advised that it only has XLR inputs and outputs. You may need to buy XLR/RCA adapters for it, depending on your system requirments. Overall I was very pleased with the 5i. I only sold it after upgrading to the 30SE. Good luck.
