Is AA scheduling the 8am departure with a flat bed-equipped aircraft in November? That flight was usually run by a 332 with flat beds up front, but as has been discussed in the AA forum, the 332 has been pulled from the schedule in the medium-term future due to fleet storage. There's a possibility that a 788 fills in for the 332 if/when demand recovers, but I don't know AA's long-term plans here (and I suspect AA doesn't either).
EDIT: I now see that you were the OP of that thread in the AA forum. I guess the answer to my question is "no" then, in which case my recommendation would be to wait to see if AA adds the 788 back to the schedule. If you're concerned about a fare increase or have some other pressing need to book now, then I'd go for UA to EWR, primarily due to the value I put on having a flat bed on transcons and the terrible LUS 321 F seat you'd otherwise get on AA.