So, the short of it is - US may be a good option for you once we actually know how the aircraft is configured, and after we have gotten some trip reports next month....
I haven't re-read this thread, but I think US came up as an option because Envoy is relatively inexpensive. Certainly not because PHL is convenient for someone who lives in New York City, like the OP. But I imagine if they do get lie-flat seats and if the service levels improve then the value equation might change. At least I'm sure that's what US is hoping for...