While flash is very doable in a shorter time span it doesn't stretch me as a writer so much nowadays (it used to as I had never written less than about 14,000 words and so flash was so very hard to do.) I like the idea of longer stories (3-5,000) though getting them done is more taxing time wise.
I love humour and think I write it well, (lol, though my competition results don't really support that.) Other than that I actually like going with the flow of a competition theme and the more unexpected the better in a way as that makes the plot construction more of a challenge (I was bereft of ideas for the Sounds of Silence originally, but google and a lot of thinking gave me what I thought ended up as a good story which I took more pride in as it had not been easy.)