After a string of 737s, got the opportunity to fly the 321 last week.
Gotta say… the seats *are* noticeably wider! So much more comfortable!
I was in an exit row, although a middle seat. But the extra width and legroom made for an almost comfortable flight.
The downside is that the seats seem to lack support towards the front of the seat pan, meaning you’re sort of perched forward because your thighs and knees are angled downwards? Dunno if anyone else has noticed this, perhaps it’s just me.
I’ve also had this experience on the Cathay regional business class seats, and have avoided them.