No this isnt a discussion on which is better or what do you have.
I added a Whelen UPS 690 hide away strobe power supply to my vehicle. It keeps popping the switch fuse. It requires a 15amp fuse and that is what I've been using but it won't hold. I've run through the wiring and don't see any shorts. Its a used system and out of warranty so don't think Whelen will help.
More than likely, you received someone else's problem, but its an easy fix. Replace the switch, your going to have to purchase a heavy duty switch, that's designed for Emergency Lights. Most switches that you find in the auto parts stores, just can't take the constant power draw, either go online, Ebay or try Napa. It'll have to be 20-25 amps, I'm not sure if you have the install directions, if not, use these. Good luck, that's a great system, very visible. http://www.whelen.com/install/131/13191.pdf