The problem is the complex has all the information. You have no idea about demand for the apartments. Also, you are usually time constrained when looking for an apartment. Together this makes your negotiating position very weak.
I have also noticed that apartment complexes will raise their rates every year. They are counting on you not being willing to move because of the hassle. I did not have this annual raise of rent in single apartments.
For example, my friend rented a studio in UTC initially for $980/month back in 2004, while i rented a one bedroom in PB for $950/month. 5 years later he was paying $1200 while I was still paying $950. The flip side of a steady rent is that I felt i could not move because my rent rate was good – I was as stuck as a home owner.
It really, really sucks to be a renter. You are at the mercy of idiots.