Key bits from the abstract:
"Analysis of health inspections conducted for over 50,000 stores in Florida shows that food safety and sanitation improve after private equity takeover, especially in areas related to food handling, kitchen maintenance and consumer advising."
"Restaurants also reduce employee headcount and lower menu prices. This evidence suggests private equity firms are not simply financial engineers but rather active operators that improve management practices in the firm. Moreover, efficiency gains do not come at the expense of product quality."
Unfortunately this does not address the main thrust of the New York Times piece, which focused more on natural monopoly sectors such as water, public transit, and emergency response. It does make intuitive sense that private firms would have less of an incentive to improve operations when buying a monopolistic entity that comes with significant pricing power already baked in. Hopefully good research on these is out there or in the pipeline, as it seems like an in-demand and under-served area of academic inquiry.
Disclosure: I worked briefly as an undergrad for one of the paper's authors, on a distinct but similar project.
0: http://people.hbs.edu/asheen/BernsteinSheen_Restaurants_June...