recommend you buy gateway 3ds card instead, today the gateway 3ds card has released a new firmware V2.2, support Homebrew and Online support check the details here http://www.dsflashcart.com/gateway-3ds-flashcart-play-3ds-games-on-3ds-xl-and-3ds-console-p-284.html
Though i tend to gateway 3ds,yet,if mt-card is your favorite,then you can buy it,after all,it was the world's first card to support multi 3ds roms and now also support pokemon x/y ,animal crossing and eshop games and so on. It has similar function with GW3DS,yet,the price is cheaper than it. If you need,here is the usa base official agent,from which i got my GW3DS : http://www.modchipwarehouse.com/mtcard-the-world-first-3ds-card-to-support-multi-3ds-rom-p-15.html