NOOB: Supercard vs. GBA MP

Ok, basically the title says it all, i am wondering which one is better, the Supercard or the GBA MP. I will mostly use it for movies and music, (however, i will download the moonshell player anyway) so I was wondering, which one has the best quality as far as sound, viewing quality, graphics, the whole enchilada (did i spell that right...)
I would also enjoy downloads such as NDSMail, DS ORGANIZE, etc. and I have a 1gb SD card, so I will need the SD version of one of the two adapters.
Oh and before I forget...call me fancy and all, but I like a customizable or "pretty" title screen, lol, and I saw a short clip of the Supercard, its when you turn the DS/GBA on, it goes to this little scroll screen...a very ugly one that si very very plain, so I was wondering, if that is customizable or changeable. I like the setup of the GBA MP however. :)
And last question: Do I need a device such as PassKey or Superkey to run it with two screens on the DS/DSLite?
Thanks for putting up with these Noob questions.

Okay. Do NOT go with GBA MP. Go with the M3. And you WILL Need a PASSCARD for dualscreen. Not sure on Supercard, but GBA MP CAN'T play NDS. So go with M3 SD. Better then the Supercard.

Passcard uses no game for verification and works in sleep mode. Size of a normal DS cart.

I did much needed research today on the Supercard, and I really really really dont like it as much as the GBAMP or the M3. And Since I narrowed it between those two, then I have decided to go with the M3 SD, based upon your last post. SO IM GONNA GET THE PASScard3 and M3SD :) Is that ok?

Yes, that will work. That's what I wish I would have gotten...I have a Supercard SD and I have to convert everything into Supercard format. But then again, I saved 20-30 bucks.

M3 is definately a good choice, bud.