I had a thread here where people talked about it
>>646, but uhh...
There's the old Witch Hunt translation, and also a Umineko Project version with flashy VN engine stuff. There's an option to use the Witch Hunt translation instead of the "modern" one, which the Witch Hunt people were hired to do so I'm not sure what the difference is. I don't know what the Steam or Mangagamer versions are, either. Man, this is such a mess.
I keep procrastinating about reading it...