I have used the 6.5 version and it works well with the exception of the "jump to" drop down box shows the name of the forum but will not allow access.
You cannot run the accelerator as it will show the forum as soon as it jumps to .php . I disabled the accelerator (the option in the CP) and has worked great for a couple of months now.
Sorry, I do not have the 6.6 either... would like it though.