T-Mobile US CEO John Legere has had an eventful week at the Consumer Electronics Show in Las Vegas. He was thrown out of AT&T's CES party Monday night after the company detected his presence. Today, he got on stage to announce T-Mobile's latest initiative, and he unleashed a stream of curses and insults at competitors AT&T, Verizon, and Sprint.

Family plans are "total horseshit… nothing more than a contract on super steroids with staggered dates—a complete life sentence," Legere said. "Sprint is a pile of spectrum waiting to be turned into a capability. Right now, their network is completely horrible."

AT&T, meanwhile, is a "total source of amusement for me," he said, blasting the company's plan to charge content providers for the right to bypass data caps that hinder customers instead of just offering unlimited data like T-Mobile does.

Legere, wearing a T-Mobile T-shirt and holding a can of Red Bull, even said he plans to send a cease and desist letter to AT&T "to stop their advertising that say they're the fastest." Cellular companies often claim to be the fastest or biggest network—naturally, T-Mobile today said the latest numbers show it's the fastest.

"This industry blows. It's just broken. It needs change," Legere said.

His speech today wasn't all bluster, though. T-Mobile said it would pay off early termination fees (ETF) for customers who switch from AT&T, Sprint, or Verizon. "With an eligible phone trade-in, the total value of the offer to switch to T-Mobile could be as high as $650 per line," the company's announcement said. "ETFs can cost as much as $350 per line. Multiply that two, three, or four times for a family, and switching becomes an extremely expensive proposition."

T-Mobile argued that family plans lock people into their carriers for much longer than two years because "with staggered expiration dates and early termination fees, they’re really locking you in forever."

T-Mobile said its offer to pay off early termination fees is good even for families. Details are as follows:

Starting tomorrow, customers from the three major national carriers who hand in their eligible devices at any participating T-Mobile location and switch to a postpaid Simple Choice Plan can receive an instant credit, based on the value of their phone, of up to $300. They then purchase any eligible device, including T-Mobile’s most popular smartphones, now priced at $0 down (plus 24 monthly device payments for well-qualified customers). After customers get the final bill from their old carrier (showing their early termination fees), they either mail it to T-Mobile or upload it to www.switch2tmobile.com. T-Mobile then sends an additional payment equal to those fees, up to $350 per line. Trade-in of their old phone, purchase of a new T-Mobile phone and porting of their phone number to T-Mobile are required to qualify.

Family plans at T-Mobile "start with one line at $50 per month for unlimited talk, text, and Web with up to 500MB of 4G LTE data," the company said. "They can add a second phone line for $30 per month, and each additional line is just $10 per month."

While T-Mobile lets users pay for handsets on a 24-month installment plan, the company noted that it has eliminated annual service contracts, saying customers should be able to switch whenever they'd like.

AT&T last week announced that it would give T-Mobile customers up to $450 in incentives to switch, in a move widely seen as an attempt to preempt T-Mobile's announcement.

Legere said T-Mobile has turned the ship around in customer numbers. While T-Mobile lost 2.1 million customers overall in 2012, in 2013 it added 4.4 million net new customers, Legere said. That includes 1.645 million new customers in the fourth quarter, about half postpaid and half prepaid.

T-Mobile is also hoping to ride high on its pending acquisition of more than $3 billion worth of 700MHz A-Block spectrum licenses from Verizon Wireless. Verizon had to sell off spectrum in order to gain approval for a separate spectrum purchase. T-Mobile CTO Neville Ray said in his 14 years at the company, "I have never had a weapon like this in my arsenal. We are going to frighten the crap out of AT&T and Verizon with that spectrum."

Sprint and Dish are reportedly considering bids to purchase T-Mobile. Without naming them, Legere said the rumored buyers are just "spectrum with no legs." He said he believes US government officials want T-Mobile to remain a real alternative to the biggest carriers. Even if T-Mobile is acquired, the brand and its attitude should live on, he said.

"What we're doing, in any scenario, will prevail," he said.