I've just returned from France and want to share information about the Versailles "Opera Experience" membership ticket.
If you've looked at the official Versailles ticket page [ https://en.chateauversailles.fr/ ] -- go to "Choose a Ticket" -- you know there are many different ticket options. I chose Opera Experience because I was buying a ticket to a ballet performance in the theater of the Chateau, and Opera Experience gave a discount as well as free skip-the-line entry to the Chateau, gardens, Grand and Petit Trianon etc. for a year.
I wasn't disappointed! The ballet performance was wonderful, and they have a full season of operas in the theater as well as classical music concerts in the chapel for those who live nearby or get to make an extended visit to the area. The skip-the-line feature was great. HOWEVER ... here are some important caveats.
1) You must pick up your Opera Experience card in person, with your ID, at the billeterie, which is only open on weekdays. So if you're arriving at Versailles on a weekend (or, for that matter, a holiday) you won't be able to enjoy the benefits until the next weekday when you can get your card.
2) They want you to paste a small photo of yourself on the Opera Experience card. I didn't have one, nor access to a printer, nor glue. Luckily my hotel front desk was kind enough to take a photocopy of my ID, cut it out with scissors, and glue it onto my card. I should have asked them for the cut-out bits of paper so I could shred them by hand; it bothered me slightly that I neglected to take that identity-protection precaution. I want to believe they're trustworthy and wouldn't try to steal my identity, but if I had to do this again I would ask for the paper scraps. If doing this in future, I'll bring a spare passport-size photo and some tape.
3) The year's membership runs from late August to August according to the opera/ballet season. So acquiring it in July means I would only get a couple of months' benefit. If I were to get a chance to return to France, say, next spring, my "year" of membership wouldn't apply.
4) If you want to buy a CD or DVD of any opera / ballet performances, there's a huge selection on offer at the billeterie. Supposedly these are also sold online, but each time I tried, the purchase page said they can't ship to the USA. (Probably because of tariffs, but they don't mention a reason.) So, if you live in the USA and want to buy one, do it while you're there.
All of that said, it was wonderful to have three days to explore what Versailles has to offer. And I still didn't see everything!