Personally, I love my 3DS charging cradle. I have it sitting on my desk, and it's very convenient to just plop my system onto it when I'm done playing with it, rather than digging around for the cable. That being said, as the other reviews have stated, this is for the original 3DS, not the 3DS XL.
However, as much as I love it, I would NOT pay $30 for the cradle and charger, as I am fairly cash-strapped. Nintendo apparently agrees with me, since you can pick up both the cradle and a new AC adapter from their website for less than $15 (but they are listed separately, so you have to make sure to get both if you need both). The product is the same in both locations, though, so whichever site you choose, you're getting a good item.