Airbus are nervous, jiggly and constantly jittering along as the avionics happily acknowledges the plane is within envelope. Boeing planes feel more damped and they don’t remind me of my flight stress as often.
But the Embraer?! I flew one over the English Channel, windy and all that; and yet, it sailed along gently.
But I'm convinced I can feel the difference between them and the A321. Maybe because of the lengthy fuselage, but it always feels much more comfortable.
I've always found A320s more comfortable. It's a big reason why Jet Blue and Virgin are generally much more comfortable than Southwest or other 737-based carriers. For seat pitch the thickness of the seats can matter, so the fact that Jet Blue and Virgin had more modern, thinner seats mattered for legroom. And of course you can add and remove rows. But thinness doesn't matter for seat width and everybody uses 6 abreast rows, so there's little a 737 carrier can do to make up the difference.
The 737MAX carries forward this handicap (737 has a circular fuselage while A320 is more elliptical), so Airbus will continue to have the leg up in this regard for the foreseeable future. Newer planes like the C-series provide even greater width[1], and considering the C-series is basically Airbus now that's just more reason to prefer Airbus when booking. Indeed, given that most 777s have been converted to 10-abreast seating in coach[2], I'd prefer an A320 (or preferably a C-series, though I haven't flown one, yet) over any Boeing plane if flying coach.
[1] The configurations so-far have been 18.5" for window and aisle, and 19" for the middle seat. 19" is like business class on Boeing planes! Compare that to a 737 where the typical seat width is 17". That's a huge difference, especially if you're traveling alone and are the conscientious type (i.e. avoid rubbing shoulders).
[2] From the originally envisioned 9-abreast configuration. Apparently the 777X is being designed for 10-abreast and will more seat width as compared to the 777, but I'll be surprised if it provides better width than a comparable Airbus plane. Boeing seems singularly focused on the demands of the big American carriers, and they couldn't care less about coach comfort.
But the nicer airlines offer general legroom's that's survivable - some budget airlines my knee is basically in somebody else's back (thinner seats help here).
My shoulders literally protrude into my neighbors' personal space, and I can't do anything about it. Even if I wasn't as athletic, my frame is built that way. Sucks for them, sucks for me.
As a thin American who observes many corpulent Americans flying, I would think seat width would be a big issue. but then I see large people squeezing into small seats and realize that my screams of protest are in vain.
Carry on. thanks at least for bringing up the topic, it's a real thing.
In the last 6 months I traveled between Amsterdam - Bangkok twice (11 hour flights) both times using KLM, and although they aren't as cramped as some other (cheaper) airlines I upgraded my seat every single flight to get a bit more leg room. But I can't compare to other (premium) airlines yet.
It therefore makes sense that the Dutch flag carrier has slightly more generous leg room than the norm.
Generally my experience is that US carriers will select the cheapest and densest configurations, especially for domestic routes, including Hawaii. They've been applying this to transatlantic routes recently as well, but I think they'll do this globally as refits occur. It all fits with the pattern of a race to the bottom that is horrible for customers and staff that turn up every day to get us safely to our destinations.
I think EU and other global carriers are at a different stage on the race to the bottom. There is still some differentiation between national and budget airlines. There are consumer protections and regulations that US air travelers could only dream of. In terms of outlook, I see these comforts diminish with future recessions and pressures on the airlines.
The major American carriers mostly compete with each other and Southwest.