I am so glad I asked. The 77W actually has a better schedule for me than the 787-9. I had incorrectly assumed that the newer aircraft would have better seats. Thanks for setting me straight.
But: You kind people have made my plan to wait for a LH F seat at 110k miles look 10k more expensive. It's now a 50k bump from business class rather than 40k. Ouch. If I lose a 77W seat by waiting, that would hurt.
UA’s 77W Polaris is a really good hard product, but UA’s 787 business class seat is also good, especially if you can get a D or E seat so both seatmates have direct aisle access. If you wind up on the UA 787, try to get a bulkhead seat for the larger footwells. Both UA birds’ seats are appreciably better than the LH 380 business seat. In this instance, saving 10,000 miles is a no-brainer.