I was just asked this by @GlacialNoivern and found it hard to answer in a tiny pm box. So here’s my answer. Feel free to add your own everyone.
If I am sitting down with a friend over the goban with a nice cup of Earl Grey tea (with honey) then I prefer Japanese Rules. In such a situation there is all the time in the world to explore Life&Death scoring problems and so on. Likewise, in any real-life tournament where there is sufficient arbitration available, I prefer Japanese Rules which despite it’s complexity, feels more elegant in execution to me.
However, when it comes to the online environment, I much prefer Chinese Rules. With Chinese Rules it is infinitely easier to resolve a scoring dispute by simply using ‘Resume Game’ and slogging it out (with Japanese Rules this is problematic if the opponent passes while I make extra moves). I prefer to resolve matters myself without calling a mod. I particularly prefer Chinese Rules for any tournament I am running or involved in that may include beginners.