If you have experienced First Class on a UA 737, then you have a feel for what it is like on AS in terms of seat width and pitch (with AS being .5" wider in seat width and 1-2" narrower in pitch). AS has leather seats versus cloth on UA, but the AS 73Gs and 739s do have the adjustable headrests like UA does.

AS does not have in-seat audio like UA, however they do have the DigiPlayers for mixed audio and video. I have never eaten on an AS midcon/transcon, so I don't know how that fares with UA's offerings, but I always find AS staff to be friendly and professional.