dont get r4 or m3, the cytclods is way better, http://www.cyclopsds.com , it shud tell u where to buy, it has a better menu than r4 and m3, more frequent firmware updates and more compatible games. plus its around the same price, maybe a lil more expensive, all comes in a nice tin too.
ive been using the R4DS for a long time already and i have no problem with it at all. its really easy to use too. you dont have to download any programs or whatever on your computer, you just have to update it [the first time you use] and download some rom games then youre good to go. i have a 1gb mini sd card and it holds enough games. heres some rom website that i use to download rom http://www.romulation.net/ http://nds-roms.com/?act=home
got an r4. build quality and materials appears to be poor but works just fine and there's plenty of skins and support out there for it. cyclo evo is quality and a nice interface. but not much support out there for it. the other up and coming card is tt ds. its also quality but interface seems a bit crummy. o and i have used these 3 cards so i have 1st hand experience, but its still only my humble opinion. hope it helps nonetheless.
I wouldnt purchase that if i were you, look for something that goes into SLOT1 which is R4, M3, DSTT etc. The reason why i would say not to buy that which is SLOT2 is cause they no longer produce those anymore and the support for it is gone, it also has no support for the newer games that come out and SLOT2 cards require u to convert the game files which could be a hassle and SLOT1 cards you just drag game files onto the card and play i bought a DSTT off dealxtreme it took only a week to ship.. so dunno i guess it depends how they run as i saw some people say it took em at least 3 weeks ><.