I don't think it's worth it for a 787. But a layover would be worth it for a 380 instead of 777 if in premium cabin. For me, I'm more open to having a layover on my way to vacation, but during the return route, I just want to get home as quickly as possible.

Multiple reasons it's not worth it.

1. The really narrow seats in Y.
2. The layover including having to go through US immigrations/customs, followed by a long domestic flight in Y is miserable.
3. Reliability of 787s is just not good. That just adds to the risk of connecting.

Personally, I'd take the quicker trip unless the 787 option earned more miles. As TA posted above, you'll have the experience of flying a 787 for the first time sooner or later. How important is it to you to have it sooner? That's the key question. Nobody but you can answer it.

It's really not worth it. It's not exactly pleasurable, as all long hauls can be a drag. It's a bit less dry in the air..but that's really it.

For years I tried to book routes with a 787 but always decided it wasn't worth sacrificing the convenience when the options presented themselves given the poor reviews and discussions I'd had with ex-CO/UA employees.

Finally got my chance this year on a simple IAH-DEN hop and decided I was glad I never made any special effort to ride the plane.