Im not sure on more rare.. but if your thinking about which one would people want more.. usually people enjoy rare costumes a lot more. Notice how most peoples wish lists include "any rare costumes" or something like that. however the gold press is always a good choice too if you wanted a garuntee.
Here is where they come from and then I will discuss popularity.
Gold Press: Available from completing the Hidden Mickey Quest in game and turning in a voucher at either WDW or DL.
Pink Princess Shoes: Available ONLY through trade, however it looks as if they may be released again for Halloween. (See Yavn thread)
The shoes are actually more rare because of the limited availablity, however with them being released again at Halloween then the gold will shift to being more rare only because you have to turn in a quest "in park" to get them.