The best, hands down, was a concert version of The Mikado. But I've also seen a lousy production of the same—wherein the cast is uneven, the acoustics are bad, so that you can hardly tell what's being sung.
Of course I've seen a couple of things on video, too—but my preference is for live theatrics if I can get them. So—even though I could easily have lounged at home of the evening, shuffle shuffle, drag drag, out we went.
Yeomen of the Guard is quite different than what you might expect of the team—especially if you're mostly familiar with the popular chestnuts, as I am. Yeomen is seldom performed, and I'm glad we went. The book was very Shakespearean—especially in the scenes with the Fool—and an undertow of menace imbues the whole thing, albeit that the usual Gilbertian wit is not absent.
The ending reminded me a bit of...is it The Misanthrope(?). Very unusual for lite comedy. Anyhow, all in all, much preferred it to The Merry Widow, although I much admired Gregg Opelka's English lyrics. I don't think he'd mind coming in second place to Gilbert; and really the fault there was the fluff it was hung upon, I mean the original piece. Enjoyed that, would not need to see it again. Yeomen, on the other hand, I'd be happy to return to.
Here's a little clip, not from the production I saw.