Seatguru is outdated on many seating plans. I'd trust the A3 website and ExpertFlyer. Also, not all A321 models have exactly the same seating layout (At least not at the front).
As A3 charges a fee for the exit rows these should be marked as such, expertflyer should also include a note that these are paid-for seats.
I'll let someone else comment on which of the two would be better - I generally try to sit as close to the front myself (rather than exit rows), so I don't have personal experience on them.
[edit]
I did find this
trip report. It shows a picture of row 9 and 10. I't say that based on that picture the windows seat at the second row of the first set of exit doors may the your best bet.