I had gone with the M3i Zero but the site for the updates for the card has gone down and doesn't look like they are coming back at this point. It was one of the best cards. I would say go with an R4i card. they have a large community and are always updating the software. Their latest card support DS games and homebrew apps on the 3DS. Fairly cheap at only USD $18.95 Here's a link for a shop. http://www.modchip.ca/store/product.php?productid=16755&cat=313&page=1
LOL Sorry about that. I DERPed that one. Well homebrew games I'm really not familiar with any originals just ports like quake and doom or beats of rage. Now apps I've used Moonshell which is a great homebrew media player. It'll run movies in DPG format and mp3 music . It also does great as a reader app for text files. Then you have DSOrganize. That has an internet browser, file browser and a media player. Does some other cool stuff too. Very useful apps in my opinion. They also have things like WIN95 for DS or old MAC OS for DS and the like but I've only seen those as a novelty thing like "oh look what I can do" kinda thing.