I have a CM Storm with Browns and a KUL-87 with Clears, so that's where I'm coming from here.
Your big difference is going to be the stabilizers: CM uses Costar and KUL uses Cherry. Other small differences: the KUL is much more solid than the CM, but the KUL also pings like crazy (at least the MX Clear version does).
Frankly for most people it comes down to the stabilizers, some people feel Cherry's are mushy compared to Costar. Additionally, on the custom keyset front there are some issues with GMK and Costar (wires rub), and on my KUL I had issues with an SA set's spacebar sticking.