T-Mobile is coming out with an unlimited four-line plan for just $100, but is there a catch?

Data hogs who love to consume gigs and gigs (gigabytes) of data every month will love this plan. That's because it's an unlimited plan that can be shared among four lines. Basically it's a family plan, for up to four members.

The four members will get 10 gigs to share, so 2.5 gigs each. After that though, they'll be throttled. So the hacker in the family might want to be careful with his data usage, so he doesn't slow down the rest of his family.

Even if the family of four goes over that 10 gig threshold, they won't be charged a pretty penny for overages. That's because T-Mobile doesn't have them; they just throttle customers after reaching a certain threshold.

For $100, which is a $29 price slash from earlier, T-Mobile is offering truly unlimited data, for now at least. This plan is said to be only a limited offer plan.

But, this plan will only be 10 gigs of shared data until 2016. By then, T-Mobile will probably cut it down or offer something even better.

If you're waiting to switch out of one of the Big Three, now could be the time.

The best part about getting into a plan like this is T-Mobile doesn't even do contracts and they'll even grandfather you into this plan once it expires. AT&T stopped offering unlimited plans years ago but some old school smartphone users were grandfathered into the unlimited data plan. AT&T has been on fire for throttling those who have those plans.

T-Mobile has clearly been taking notes. They know customers hate contracts, customers hate overages and customers hate to count minutes and gigs. The company has decided to rid contracts and end overages.

Just because T-Mobile is doing some customer-friendly things doesn't mean that they have good coverage, though. It depends on where you live. You may love T-Mobile or you may hate it, but they are doing some things that actually benefit customers rather themselves.

What do you think of T-Mobile? Are they a good carrier?