I'm a window seat person so shoulder room (more so than leg room) are important to me. That said, row 10 A or F are my preferred on both the 321 and 319. You're right the Embraer seats in coach are pretty good, for some reason I had a traumatic crossover flashback of the CRJ seats !!!

My last ride in coach was a few weeks ago in the back of a 757, not nearly as nice as the Airbus or Embraer family.