As has been stated, it depends on who you trade it with and what they are willing to trade in return for said card. The premiums are more varied than regular cards as they only gain more value in the eyes of collectors that place value in the premium effect. For instance, I wouldn't trade for a platinum my self as I am only interested in the play value of the card and am fine with normal cards. On the other hand, I know that the platinums I have will be more valuable in a future date so I'm not trading my platinums away unless they are for someone else's platinums so I can maintain the potential value of the card for when they enevitably rise. That's just my take on the platinum premium cards. Best I can suggest is to ask around in game to find those interested in the card, and seeing what they are willing to offer for it, then go for the offer that you view is best.