I used my 4 gig to make a memory stick, and changed it back to normal with no problem. But I also read it's good to keep a dedicated MMS around in case you brick your psp (unless you have an adapter to put your memory stick in your PC and make a new one, i think, someone correct me if I'm wrong). I know Sandisk's are good, Im not saying they're not, but the one you are thinking of buying isnt an Ultra II, so you may have problems with demanding games. I know you want to save money, and the Lexar should end up being cheaper after the rebate, even calculating the extra shipping cost. And it's supposedly faster. But it's up to you, and like I said, I haven't come across any slowdowns or anything on that Sandisk yet, so hopefully you'll be ok.