I have an iTouchDS, and while it is not the best card on the market, it does what I need it to.
Build quality isn't hard as steel, but its not flimsy like a piece of saran wrap either. The little tabs on the edge can apparently be easy to stress or break if you try to open the card. I have opened my card (will explain why in a minute) numerous times, and the plastic has not turned white from stress, nor has it broken. I just use a jewelers screwdriver carefully. Maybe the biggest annoyance is that you can feel the chip sticking out through the sticker slightly, but it doesn't make that much of a difference if you think about it.
I have had to open the card much lately because the spring mechanism in the SD slot stopped working. It got to the point where it wouldn't eject the sd card (I would have to pull it out), where the card would not stay in at all, or where I couldnt even push the card in all the way (it was getting stuck on something). However I bent a metal "clip" inside of it with the same screwdriver, and it works close to how it should now.
The firmware is a bit slow when it comes to selecting menu items, but otherwise I can't say I find much wrong with the card. I can't get real time save to work in DragonQuest V - Hand of the Heavenly Bride, but I am going to ask around and see if there is a way to fix that.
Bottom line - Cheap card, but decent build quality and does what it is supposed to. If you don't have the money for an excellent slot1 card, I would recommend this.