Umm You should go with CycloDs.. in my opinion it has to be the best flash card ever made.
Do not go with the R4!! all R4's are fake and stupid the original team that started making R4's gave up on them after a couple of months and it's very rare to get one of there originals and not worth it.
CycloDS Evolution Features
* Completely plug & play - no FlashMe, PassMe or PC software required
* 100% compatibility, supports clean ROM's - works on any OS
* RealTime Save function, allowing you to save and restore the state of gameplay at any time
* Wii connectivity in games is supported
* Full NDS download play support
* Action Replay compatible cheat code engine, comes bundled with over 300 cheat codes for over 300 games!
* Uses MicroSD card, both FAT16 and FAT32 supported
* Supports the MicroSDHC specification, allowing for high capacity memory cards
* Save type is automatically detected, no need for a save type database
* Save directly to MicroSD rather than onboard flash
* User friendly, easily skinnable interface. Both touch screen and button operation supported
* Multi-lingual user interface
* "Enhanced Mode" which provides powerful, unique features during game play. Enhanced features are activated through an in-game menu. Enhanced mode features include:
o RealTime Save which allows you to save and restore the state of gameplay at any time
o Adjust LCD brightness during game play (NDSLite only)
o SlowMotion mode which can be used to slow down game play to make fast paced action sequences easier to master
o Return to CycloDS Evolution Menu (aka soft reset)
o More features to come!
* Excellent homebrew compatibility thanks to the DLDI auto-patcher
* 2 megabytes of onboard flash memory which contains the CycloDS Evolution OS and will be utilised in the future to add exciting new features. A recovery mode is also included.
* Autoboot mode which when activated will directly boot into the last ROM or homebrew application executed
* Moonshell included to provide media playing functionality
* PassMe function (boot from slot 2)
* Supports rumble and memory expansions, without any special user interaction required
CycloDS Evolution package contents:
* CycloDS Evolution
* USB MicroSD reader/writer
http://www.cyclopsds.com