I've used a DSTT for months and haven't had a single issue, it just boots game after game after game and I've played many to completion
there's a slight possibility this might be a clone though, albeit with the exact same functionality as the official cards, so you better search for some hacked firmware on gbatemp that will remove the "clone-killer" code on the official firmware... though I've read many testimonies of people buying clones, flashing them with the official firmware and not experiencing any issue
you also need some kind of adapter to read MicroSD carts, if you don't have one already... they sell them for like 1-2$ a piece on Dealextreme too