I recently flew on the A321 - on the online check-in, it shows row 9 and 10 as emergency exit rows. So I chose 10D, as I thought row 9 would not recline into the emergency exit row - row 10.
However, I get on the flight, and see that row 9 is an emergency exit row, with loads of legroom, and 9A and 9F are missing - a flight attendant sits backwards facing seat number 10F. I think that seat number 9A is also missing, but no flight attendant in that area.
And row 10 is a regular row, just that 10A and 10F have loads of legroom due to the missing seat 9A/F seat in front, except during take-off, where there is a flight attendant opposite 10F.
However, row 9 (of which there is no 9A or 9F) have loads of legroom, much more than the emergency exit legroom on A319 or A320.
So in short, if you want alot of legroom, choose 10A/F or row 9 (of which there is only 9B/C/D/E).
And row 9 does not recline, row 10 does.

I assume that these details are corect on all A321s.