Castle says the spark is your friend but I'm not so sure.

Not only does it degrade the arming connectors over time (which eventually will fail), it also stresses out the electronic components. Not a good process with microprocessor controlled devices in my opinion. Limiting the capacitor inrush current is a good practice IMHO.

Personally, I use the Emcotec Safety Power Switch. Sparkless and neat.

Cheers,
Jason.