Learned Hangul (just the script, I have no intention of learning Korean ever). Not worth much of bragging, since it is indeed very easy, "a writing you can learn within a morning" - though it took me considerably longer.

My primary motivation was to have a sort of private semi-secret script to write my notes in, and something where syllables will be organized in blocks, which theoretically helps reading (though one has to read a lot to internalize the whole shapes to achieve this).

I have some relevant observations:

• Hangul might fit Korean language perfectly, but is really, really unsuitable for a "random European language". Not only there are many consonants missing, but the syllables cannot have an arbitrary coda, and arbitrary consonant clusters are right out.
• The above point can be remedied somewhat by (re)using historical (obsolete) letters, but:
• Historical letters have almost none computer support.
• Arbitrary consonant clusters have none computer support, since:
• There are standalone "jamo" letters in unicode block U+1100, but most applications cannot deal with them, requiring to use precomposed syllables insted
• Even if I could use standalone jamo, font support does not go beyond initial consonant+vowel+(fixed set of) final consonant cluster, anything else just displays overlapping and utterly unreadable letters.
• Syllables consisting of consonant+vowel are nicely readable, but:
• Syllables witht he structure CVC(C) are less readable, requiring bigger font size, which kind of defeats the point of readability. Especially if one wants to use morphematic writting, as opposed to phonemic one - which was my original intention, to keep the word roots unchanged.
• Thus, Latin script at smallish fontsizes tends to be more readable than Hangul at twice the fontsize.
• Korean input methods under X11 leave a lot to be desired. Especially if you want to type something that does not fit Korean phonology, you are basically out of luck.

Considering all this, I indeed do use Hangul as my private semisecret script, and intent to continue doing so.