Remember Comcast’s customer rep from hell, who insisted that a subscriber answer a barrage of questions before being allowed to cancel the service? Or the customer who was fired when he complained about a series of billing snafus, and Comcast contacted his boss? Or the technician who fell asleep on a customer’s couch? Or…well, you get the idea: Comcast has a lousy reputation for customer service based on these events and people’s everyday experiences waiting on hold, or for help to show.

But that’s about to change CEO Brian Roberts vowed today as he unveiled a multi-year plan costing about $300 million to modernize its stores, and hire 5,500 customer service reps  — including 2,000 at new call centers planned for Albuquerque, NM; Spokane, WA; and Tucson, AZ. In addition to the investments, starting this year all employees will be required to participate in customer experience training.

“Some of those anecdotes [of service outrages] have been unacceptable,” he says. “We’re going to get at this.”

Comcast says that by Q3 it expects to always be on time for customer appointments. It will simplify billing and roll out new technologies to give customers more control over interactions with the company. For example, by year-end the My Account app — launched last year — will add a Tech Tracker feature so users can see in real time where a technician for an appointment is and then, afterward, rate the experience.

“Customer expectations have changed,” says Comcast Cable CEO Neil Smit. “People want immediate gratification and immediate solutions to their problems.” The initiatives will pay for themselves if they improve customer retention. What’s more “it will take noise out of the system.”

Comcast has long said that it will fix customer service. Why should anyone believe that this time the message will take? Roberts says that service reliability actually has improved over the last several years, even as its products across TV, broadband and phone have become more complex. Service and satisfaction “are not exactly the same things.” And he acknowledges that the company will never be perfect. “The bar is always rising…You’ll always be able to ask that question.”

Still, he says that today’s announcements are “quite significant.” Smit also says that Comcast must “build back [customer] loyalty…We have to prove ourselves every time.”

A better image for Comcast might pay off in Washington, although Roberts says he doesn’t know whether the public’s low regard for his company’s service emboldened Justice Department and FCC officials to oppose the $45 billion acquisition of Time Warner Cable. “It probably wasn’t determinative, but you’d have to ask them,” the CEO says.