Yes, we recognize your name from many past posts in the X forums. I came to the same conclusion. Realizing that I was looking at rough parity between the price of an X Royal Suite vs. a comparable Silver Suite on SS Muse class, it seemed time to make the transition.
Like you, we always found the food on X to be just fine, and as we confined our cruises to M and S class ships, we had more options on Luminae. We'd always order the lamb in phyllo when we spotted it on the main dining room menu. The Luminae MD was also very attentive. We noted that we missed the goat cheese soufflé from the old specialty restaurant (while on an M class ship) and surprise, it appeared on our table the next night, the recipe having been cribbed from an E class ship.
One thing you'll discover as a pleasant surprise, if you're waiting for your first SS cruise, is that based upon the lists I've seen photo's here, their better wine by the bottle is priced at land-based retail, sometimes even a few bucks less!