I live in a unit owned by SFSU, so I can't speak about lost checks or bad maintenance. But the area is safe, clean, well-lit and has beautiful landscaping. It's also one of the only affordable places in the city if you own a dog.
I read all these bad reviews about the Park Merced area and they give a completely false impression. I've had a good experience so far, with the exception of one or two student parties that were loud and obnoxious. But good luck finding a place to live in SF for less than $2000, and I'll take occasionally loud students over the small army of beggars and panhandlers in most other neighborhoods near a park!!