The Raspberry Pis that the school received after entering the hour of code competition are great. They arrived in a really nice box and are neatly packaged. You get a case, power supply, 4GB SD card (with NOOBS), a shiny and sturdy 'getting started' guide and even a free copy of the MagPi magazine.
If the intention is help kids understand more about computers work then presenting them with what is essentially a black (well, white) box just feels a bit odd, especially when the same case is available in transparent plastic.
The case is also quite tricky to open, especially when stiff and new. There are four tabs on the bottom that you have to release before the top can be removed, and this can require a bit of a wrenching even if you have a screwdriver to hand. My 9 yr old - who's pretty dextrous after hours of Lego building - can't open one up. When I was looking at the new Pis with some of the teachers, they looked slightly horrified as I man-handled the case to remove the top and reveal the device inside.
The other problem is that these cases have no access route for either a Pi camera cable or any connections to the GPIO pins. As I mentioned in my post about the Spud game, the key selling point for kids is all the cool stuff you can connect to the Pi.
I imagine the choice of case was primarily to keep costs low. The wonderful PiBow cases from Pimoroni are a lot more enticing and even their assembly is a fun lesson in 3D shape manipulation (although the component parts are certainly more fragile and the plastic screws easy to lose). perhaps most importantly, they have slots for the camera and a ribbon cable for the GPIO pins. They're also quite a bit more expensive than the simple 2-piece cases shipped with these kits.
Perhaps a better compromise would have been something like the IceBerry cases (I don't have any to show a photo) which are more affordable but have the slots for cable access.
So if you have got one of these Pi kits, my advice would be to use the Pi with the lid off wherever possible so that the kids can see what's going on inside and get easy access to the GPIO. Keep the lid for safe storage though!