I used to have the "Executive Card" but it never paid off.
Last year, I got a coupon for 40 bucks, and the Executive membership is 110 I believe (vs. 55 for a regular one). The year before, it paid off, but only slightly and the year before that, I got the short end of the stick as well. So I went to them to just have a regular membership and they tried (twice) to talk me out of it, showing me that I "already" had accumulated 10 bucks this year, blah blah blah, and I would lose that 10 bucks if I downgraded to a regular card. (They also pulled this a couple of years ago when I first got the card and realized it wasn't paying for me to have it and wanted to downgrade, only at the time, I bought their angle.)
For me, it's not worth having the more expensive membership.
If you drop 10 grand a year at Costco, I suppose it's worth it.