Not so much better, but different specifications.
Memory choice - DDR2 or DDR3. I pretty much think that if you don't have and i7, DDR3 memory is a waste of money.
DQ or DS (UD now) - DQ boards are at the upper end of the P45 family. DS boards represent better value.
3L, 3P, and 3R boards - differ in number of SATA ports and PCI-e lanes. L's are the base model; P's are the upper end. When I was looking for a motherboard a couple of years ago, I decided on an EP35-DS3P. The L didn't have enough SATA ports, and where I live (Saudi Arabia), no one had an R in stock.