Hi,
I prefer 757 because of more coach bathrooms and more seats in FC so better chance of upgrade. I don't think Airbus single aisles are more confortable than 757 but they have better seats than UA does on the 737's. Southwest has some nice seats on their newest 737's not sure if they are -700 or -800. I also like UASIR A321 which is around the size of 757 , has 8 or 9 rows of FC and has an extr4a bathroom like a 757 but its around row 20 or 21.
I don't like that Airbus's in flight entertainment on UA seem to reset the channel I have selected all the time like each time a flight attendant or pilot makes an announcement I have to reset volume and switch back to 9
Steve