I used the pass last year and it was great.
I think it is best to get Rick's book for Paris, the biggies (louve, orsay, versilles ect..) are in Rick's book, he includes maps of these attractions and the seperate enterences if you have a pass.
There are seperate enterences, most often using the group enterence, just show your pass, I saved an hour at the louve and both 2 hours at versilles and orsay!
I consider the pass a very good deal, and it was great to skip lines, there was security but was pretty quick. Have a look a Rick's book to know where those seperate enterences are!