Generally speaking, I think privately owned and operated systems would be more efficient. However, there are times when the private sector has failed to deliver, and government must step in. In the broadband access area, it is clear there are plenty of gaps, even in developed areas.
The greed and arrogance of the private carriers is ugly.
There are many examples of municipally owned utilities, such as water, sewage, gas, and electricity. I don't know what the overall experience is in terms of service quality, reliability, customer service, and rates. I do know of examples of good and bad on both sides.
For instance, one city has municipally owned gas and water (separate departments). The water works operates very efficiently with low rates, despite aging pipes always breaking. The gas works operates poorly with very high rates, explosions, and many complaints. Why one city department would run well and the other poorly I can't say.
Historically, the United States was well served by a privately owned regulated telephone system. Other countries had government owned telephone systems that weren't as good. Yet in contrast, that business model failed with Western Union and telegraph service; both the company and regulators made bad decisions in the 1970s.