Is T-Mobile a good choice for my family?

So CES 2014 has been wrapping up, but one thing that happened in the cell phone realm was T-Mobile putting it out that they will pay your ETF (Early Termination Fee) for you and/or your family to switch to them.

My Family is currently on AT&T

5 lines for about $180-$200 a month. Three Iphone 4S's and one Iphone 5. We get unlimited text, but only 300 mb of data each, and 700 minutes shared between the 4 of us (one line is a business line). We have been in our contracts probably about a year all together so far, maybe the business line longer.

Now, to T-Mobile.

They have a 5-line plan for $110 per month, that gives us unlimited talk, text and data (500MB of 4g speed, and unlimited 2G speed when that is used up). And since CES, we may be able to get out of our AT&T contract soon and with a low cost from that, and turning in our phones to T-Mobile for credit, because all of our phones have had otterboxes and screen protectors to keep them in VERY good condition, in my opinion.

So the question in my dad's mind, as my dad and I both are tech-savvy and know that there could be consequences to this T-Mobile idea is:

Is T-mobile a good service? Or at least good enough to the point that taking about $80 off of our monthly bill for more data and minutes would be worth it?

Is there good customer service under T-Mobile? If there are any articles that are easily out there to know anything about the service, that would be of great help to be in the answer, and

Are the speeds very good under T-Mobile? We live in an area where their coverage map says we will have "good" to "great" 4G LTE coverage, in Western Colorado, and will they be comparable to AT&T? Or will they possibly get there over time?

I would appreciate a longer answer, but if at least there would be enough answers just stating " Yes, No, Yes, Yes, overall You should do it for savings sake", those answers will also be appreciated.

Also, anyone with T-Mobile experience, please try not to bias it all too much. I have done much research so far, but just like AT&T vs Verizon vs Sprint vs whatever else, there will always be those who love it and those who hate it. I just want facts, and not bias of them not replacing your phone because someone threw it in a street.

Thank you for any help, as this may become a possibility for my family, and I'm sorry for all the reading.

I've been a T-mobile customer for a long time and I think it's a good service. To me it completely depends on the coverage. If T-mobile coverage is good in your area, I would get it. There are certain areas where T-mobile signal will be weak but AT&T will still work, but 99% of the time I'm in a good coverage area.

The speeds are perfectly fine, I've run speedtest and gotten 30mbps down and 16 up on LTE with my Nexus 5.

I haven't had big issues, but their customer service has been fine for any questions I've had. They have online chat, forums, email, and phone contact.

Check the map, and if the places you normally go are in a good coverage area, I'd make the jump, it's a much better value.