Today the revealer helped quite a bit, as we figured that (37A: Platform ... or something that appears four times in this puzzle? (SOAPBOX)) out before we got any of the rebī, and after MOONS[TONE]S (29D: Opalescent gems), we knew what we were looking for. I couldn't get "Budapest" out of my head, though, in the SW, but luckily, Frannie got BAK[LAVA] (65A: Honey-soaked dessert) and BRATIS[LAVA] (42D: Capital on the Danube), so everything worked out just fine.
It seems like it's been a while since we last had a rebus, so that was nice. It was less-than-perfect that two of the answers had gratuitous esses in one direction ("seizes" & "moonstones"), but we'll let that pass. There was a good amount of Scrabble-y letters, with JAMBS (1A: Side pieces) (another gratuitous S!), JIBES (26A: Agrees)("), JINX (26D: Curse), KARAT (49A: 24-____) (tough one), KABOB (49D: Item purchased at many a food cart), OKAPI (34D: Relative of a giraffe), and others.
As always, there's a smattering of EMIR, ANIL, WNW, but not too, too much. Anyway, I like a rebus puzzle, so they have to go pretty far afield to wreck it for me.
Oh, I almost forgot the symmetrical cities of PASADENA (6D: Annual parade locale) (really? Frannie must have gotten this one) and BRUSSELS (38D: European city whose airport is the world's largest chocolate-selling point) (interesting).
All in all, a decent Thursday.