I currently have a Charge, purchased from Costco about 1.5 m ago. I have another 1.5 m to trade it in at Costco. I was hoping to get a SGSII, but thats out now. Should I trade it for Bionic? Looks like I'll have to drop around an extra $130. What is the resale of a charge vs bionic? Hoping to get the Prime in a few months.