It really depends on the capabilities of board that is driving the LEDs.
Assuming the doesn't limit what you can do, an RGB led will let you choose basically any color for the blade and clash, but brightness will be less for some colors. A blue-blue-white star will generally have two LEDs on, while an RGB star will only have two LEDs on if you chooise cyan, yellow or purple colors. For red, green and blue, only one LED will be on.
My particular solution to this problem is to make it possible to swap the LEDs out, like so:
LED star adapterAs for weather an RGB star is "bright enough", well, only you can answer that question. Personally I find that my string blade with 100 half-watt LED in it is still not bright enough, so I'm probably not the right person to ask. :)