I don't have kids myself, but friends have shown Firefly to theirs and I'm happy to report that it still holds up. There's hope for the future yet.

The writing of Firefly was top notch and still holds up great. The MCU tried to imitate the style and mostly failed. But it helped that Firefly was much less overwrought in general.

My kids liked it when they were younger teens. But we'd also already been through Buffy, which they liked.

There were a few times we cringed a bit (with both shows) but overall stood the test of time. I didn't watch Buffy & Angel first time around, so it was a bit of a cultural moment I got caught up on. And it was nice to revisit Firefly, the little bit of it we got.