The UX (both keyboard and software) was .. just awful.
Subsequent OS releases fixed most of the software problems, but the project had lost a lot of steam and goodwill by then. (They also lost a lot of goodwill before the release when Microsoft announced that they'd gotten Windows XP to work on the laptop, and the OLPC project announced that it would be available as an alternative to their own linux-based OS. [0])
As a result of the really, really bad experience with the Give 1 Get 1 campaign, OLPC instituted minimum order quantities of 1000 laptops (or 100 laptops if you ask nicely. The OLPC XO-1.5, a new motherboard for the XO-1 laptop, was also available in minimum quantity 100). The latest version of the laptop, the XO-4, has a gigahertz ARM processor and either 1 or 2 GB of memory. However, there are only 3 ways to get one:
* be in a country or school program that purchased the XO-4
* have a quarter-million dollars to spend on 100 laptops
* convince the OLPC project to give you one so you can develop educational software for it [1]
If you buy (or hear someone talk about buying) an OLPC laptop, it's almost guaranteed to be an XO-1. Unfortunately, most of the software (including the OS) is now developed against the much more powerful XO-4. This means that the XO-1 is now in a similar state now as it was when it was released -- almost everything is slow, and your precious RAM fills up quickly.
Exemplifying the state of the XO-1 laptop is a memory leak [2] in Sugar (the desktop UI). On the 1-2GB XO-4, it is not considered a problem:
> The leak has negligible impact on XO-4, XO-1.75 and XO-1.5. On these laptops we recommend that you restart Sugar at least weekly.
In the XO-1, however, idle memory consumption is easily 150 MB, and you can run out of memory in less than one day. The official fix is:
> On the XO-1 we recommend that you restart Sugar every few hours
I feel bad about the whole situation. The OLPC organization seriously tried to make Alan Kay's Dynabook real, and they produced a really cool piece, well-designed piece of hardware. (Not to mention a very well-documented hardware-software pair. [3][4]) It's a shame that they got in way over their heads by trying to develop the hardware, develop drivers for the hardware, develop a custom desktop environment, develop child-friendly userspace applications, and sell them in single quantity, defend themselves from critics, and also attract sales contracts from foreign bureaucracies.
[0] https://tech.slashdot.org/story/08/05/15/2320243/microsoft-a...
[1] http://wiki.laptop.org/go/Developers_Program
[2] http://wiki.laptop.org/go/Release_notes/13.2.9#Sugar_Memory_...