Well, the A320 First seat is a few inches wider than the 767 Business seat, but the Business Seat is much nicer, more comfortable (especially for a transcon), and you will now lose personal video.

If you can, I'd work with UA to see about getting a 777/767 flight with a Business cabin.

As for the 777, I find Row 8 is great, period. You will actually most likely have a B type, as an SFO-IAD plane is most likely moving on to Asia. The issue with Row 9 is the flight attendents store there bags behind it, so you either can't fully recline, or they pester you to raise the seat everytime they need to get something.