We got my father a Windows tablet for Christmas - an Asus VivoTab Note 8.
Being able to run a full copy of Windows on a tablet is great - you can actually use a tablet for 'real' work. There are a lot of tasks which are still impossible on iOS or Android due to a lack of software - something as simple as transferring data to/from a Garmin serial GPS, or even copying a few files off an optical disc.
The Intel Atom processor is more than up to the job (it can encode video slightly quicker than my 3rd-generation i5 laptop), but I wouldn't settle for less than 2GB RAM, 64GB SSD + Micro SD slot and an 8" screen.
The desktop side of things is difficult to use with just a finger - a mini-mouse or the Asus' Wacom stylus make a big difference. But the Metro Modern side of things still needs a lot of development and the app store is rather underpopulated.
Overall it cannot compete with Android for reading books, watching videos & playing games. But for any real work it is in a different league.
If only someone would produce a dual-boot Android & Windows tablet.
Goes off to search for an Android build which can run on a Windows tablet from a Micro SD card....