Super Plasma GT vs. Silverstars

[ragingfish]

Ok, so I've been flipping between silverrstars and super plasma GTs to try and find the best bulb...and honestly, I can't seem to figure out the difference. Has anyone else used both of these bulbs, and can you shed some light on which you think is brighter? They seem identical to me, and if that's the case, I'm better off next time with the silverstars since they're so much cheaper!