We'd love to tell you about the games themselves, but StreetPass Mii Plaza has crashed on us every time we've loaded up the new Shop page - reports on NeoGAF indicate others are also struggling with crashes. One NeoGAF user reports each game costs £4.49 ($7), while all four can be obtained in a value bundle going at £13.49 ($21). There's no official word from Nintendo, perhaps indicating the patch went out earlier than scheduled.
What we can confirm is another feature in the new update, and that's the ability to create save data backups. Accessible via 3DS Data Management in System Settings, the new feature lets you create or restore backup save data, but only for software downloaded to the 3DS. The new feature may not be compatible with every single game; we tried it for our freshly obtained Animal Crossing: New Leaf, only to be greeted with a message telling us "this software's save data cannot be backed up."