I'd echo the sentiments above - ensure you have the user requirements down to perfection before committing. That having been said I have experience using platforms like these as educational aids, setting them up for easy browsing of material relevant to a company or academic institution by people not awfully experienced with computers - an experience that got positive feedback from the less computer literate.
They are pretty lightening fast to boot, but I have no experience of how this drops off over time, or the user experience for sharing files or downloading non-app store programs to the desktop. Compared with many devices in their price range, however, I have found them to offer a lot for a relatively low price. You could happily run a home business from one of these if all you need is essential office software, some stationary design/letterhead design software and an internet connection.
One word of warning: The majority storage is Cloud. You only have 16 GB of local storage, which isn't a lot if entertainment is an additional requirement on top of the generalities of daily use. If you or your mother (or any other potential user) have any qualms about the cloud, you should think on this point first and foremost. Personally I think the cloud is a great thing, but as someone researching distributed task allocation and communications - the concept of ephemeral storage is always going to sound good. If you have any data privacy concerns, definitely read up beforehand.
Then again, 100 GB of cloud storage is pretty nice - saying it is 'free' with the device (and transferable to all other devices - for instance a family photo album may be keyed to be shared with select google users - allowing you all to contribute to the pool no matter where your life takes you).
ADDENDUM: Apparently the cloud storage is only viable for 2 years from purchase. You may want to look into how expensive the subscription schemes are if that is the case and the device is intended for 3 years or more of use.
FURTHER ADDENDUM: All models use System On Chip (SoC) processors, a relatively new innovation that stacks processor, memory and sometimes graphics processing on a single device (usually an ASIC after FPGA prototyping). In the case of samsung, they offer a 1.7 GHz dual processor (the ARM Cortex A-15). These are low power, run pretty cold and are highly stable - for those interested in the smallness of these things - they use 45 nanometer transistor technology for this particular device, not our smallest, but pretty impressive.
ARM is also highly supported with a good knowledge-base in the software development and PC-repair industries; they also have tonnes of documentation for the home-programmer or techie who is called upon to help fix a bricked device or bring something novel to what at first appears to be a constrained consumer device. It is an architecture that I, personally, enjoy working with a lot.
Funnily enough on the gaming side that Vikarion brought up, the Exynos Dual (the brand name of this SoC configuration) is capable of mid-tier gaming along the lines of HTML 5 on-line 3D gaming and some more limited games. It won't run something that we as gamers would consider 'worth having' but for general entertainment it suffices. With 6.5 hrs of battery life it is suitable for inter-state travel entertainment too - though that is 6.5 hrs by an unknown metric (they probably left it after boot with a stop watch next to it, no stress test).
Downsides: Consumer targeted device. Likely inflexible and only has a few tricks. Very limited local storage. Data privacy concerns about Cloud storage depending on your local laws on information ownership (afaik Google are pretty good about Cloud atm, but this is an area experiencing legislative growing pains right now). Need to renew cloud subscription after 2 years.
Upsides: Low power, doesn't run hot. Good processing power for such a cheap device. BIG capacity if you consider cloud to be a-okay. Capable of running a full suite of low level gaming and entertainment packages. As previously stated you could probably run a home business off of one of these alone.
As for alternatives, I haven't had a chance to look yet as I am procrastinating at work right now.