One big difference in EWR for 737 vs 320 is the number of LGA trips.
The 737 has roughly 10% LGA trips while the 320 is over 60%.
I've been flying the line in EWR since late April on the 737 and have not done a single LGA trip. A friend hired two months earlier on the 320 is flying two to three LGA trips per month even though he freezes all LGA trips in the lowest pool.