I won't be building a new computer for a few more years, as I currently can't justify the cost of replacing my build, but when I do it'll almost certainly be a SFF build.

I've seen a number of people who have built tiny custom cases, and the challenge of both building something like that and getting everything to fit in it is super enticing. Definitely seems like the challenge and cool factor of fitting tons of power into something tiny is making a lot of people consider such builds over traditional mid or full tower machines.