The Pulstars are a rehash of an old idea. It comes out every few years, gets a few new people buying them and swearing by them. Then when real testing is done, they are usually dismissed.
Direct Hits is another similar idea recently. Nology Plug wires also have that capacitor storage effect.
What the capacitor does is very slowly store energy into it as the voltage going to the plug gap is rising(which occurs before the spark). This actually delays the spark a fractional amount, but it can be a degree or so at higher RPMs. THEN, when the plug gap flashes over, and the voltage across the gap drops, the energy stored in the capacitor is released very quickly. So quickly that it comes and goes before it can have any real effect.
But, thanks to a phenomena known as persistence of vision, it will appear much brighter. Even though it only had a larger discharge current for nanoseconds.
Nology effects have been pretty well dismissed by most people, and this is a very similar function.
I have heard many DSM gurus swear by some of the various platinums, and I'd give those a try before gimmick plugs.