One week ago, Verizon surprised everyone by announcing a new unlimited data plan. AT&T, Sprint, and T-Mobile swiftly responded with unlimited plans of their own. The competition means many users have access to attractive unlimited plans for the first time in years. Time for you to switch plans? The answer may be yes.

Verizon  had killed its unlimited data plan six years ago, and resisted pressure to offer unlimited data ever since. It even released ads arguing that most people never use more than 5 gigabytes of data a month and don't need unlimited plans. What changed? Verizon faces growing competition from T-Mobile, which has gone all-in with unlimited data plans for its post-paid market. And Comcast has announced plans to begin selling wireless service which will actually use Verizon's network but create even more competition for mobile data.

Verizon's move set off something of a bidding war for mobile users. Sprint and T-Mobile immediately improved their unlimited plans, adding tethering (the ability to use your phone as a mobile hotspot) and HD video streaming to their plans. AT&T, which previously only offered unlimited data plans to DirecTV customers responded to Verizon's move by removing that restriction so that all customers can buy unlimited plans. But you still can't tether without paying extra.

Should you switch plans?

It all depends on your usage patterns and priorities. Gizmodo has provided a helpful comparison of the pros and cons of each plan. Here's a very quick look at what each is offering:

1. AT&T

AT&T's only change in response to competitive pressure is its $100 unlimited data plan and $40 for each additional line. (I should note that these and all other prices assume auto-pay. If you don't want those automatic charges, prices are slightly higher.) As you likely know, all unlimited data plans reserve the right to "throttle" your data do a slower speed if you go over a certain consumption limit. In AT&T's case, that limit is 22GB per month.

If you're already an AT&T customer and want to stick with that carrier, that may make the decision relatively simple. On the other hand, if you want free tethering, you'll have to look elsewhere. If you like watching video over your mobile network and you're a DirecTV subscriber that's an argument in AT&T's favor, since AT&T "zero-rates" DirecTV video. Translation: It won't count against your data limit (or throttling threshold) for the month.

2. Verizon

Verizon was the one that kicked off the unlimited data wars, and most experts agree it has the best network coverage in the nation. Unlimited plan pricing is $80 for a single line, $140 for two lines, with prices going up $20 per line from there. Verizon also was the first to allow HD video streaming, although now the others have followed suit. And, like every major carrier except AT&T, it allows 10GB of tethering as well.

Be aware that Verizon uses different technology from other carriers, which means you may or may not be able to use your current phone if you switch from a different carrier. There are also some Verizon customers who still have unlimited plans from before the company stopped offering them and have hung on through thick and thin. If that's you, depending on your current plan and how much data you actually use (i.e., whether throttling at 22GB would affect you) it might be time to finally consider a change.

3. Sprint

The biggest argument for Sprint is short-term savings: If you're a new customer, you can get a single line for $50, two lines for $90, and third, fourth, and fifth lines for free--but only until March 2018, at which time all these prices go up. Still, that's a heckuva good deal for a year's worth of service--and who knows what other prices and options will be available by then? Sprint reserves the right to throttle data at 23GB per month and it allows tethering and HD video streaming as well.

4. T-Mobile

Competition from T-Mobile is likely what set off the unlimited data wars, and the carrier has been building out its network and improving coverage at a rapid clip. It has a limited-time offer of $100 for two lines with unlimited data--a price that sounds pretty good compared with the others but is actually great when you note that this price includes all taxes and fees. One line is a slightly less impressive $70 (still a great deal including taxes and fees). Three lines are $140, with prices going up $20 per line from there. T-Mobile also only throttles data usage after 28GB, not 22 or 23 as the other carriers do.

If you watch video on your mobile device and you want to watch in HD, you will have to enable that through T-Mobile's app. If you don't care about HD, T-Mobile has an appealing plan called Binge-On in which lower-quality video streams from Hulu, Netflix, and YouTube don't count against your data threshold.