Well it all depends on what you are using it for- close up or stage. For stage, hands down get a swami, I prefer the TT Swami because it requires less prep. In close up situations its nice to have the super sharpie because it hides so nicely, but it is not as easy to take on and off. In the end you want to have them both anyway, so get the one you will be using first and then get the other later.
For stage get the swami? Are you serious? Have you actually done a trick with a swami on stage? Even the front row will squint trying to read what you put down. Super sharpie makes so much more sense on stage. And the regular flesh coloured swami hides so much easier than the black super sharpie.
Jessicamagic, if you are new to mentalism and just learning to try things out for the first time; I recommend just getting your every day lead swami gimmick. Come up with some ideas and start performing to friends. If it goes well and you enjoy using it, then have a think about investing in a super sharpie.