At T-Mobile’s recent Un-Carrier 7.0 event, CEO John Legere said every new phone sold by the carrier will get free Wi-Fi calling. Customers would have been happy if the news ended there, but that’s just not Legere’s style; instead, he announced a new Personal CellSport router, which T-Mobile customers can use for free (there’s a one-time $25 deposit) to ensure the best possible in-home coverage.

We tested it out here at our office, where cell coverage isn’t the greatest (that goes for Sprint, AT&T, Verizon and T-Mobile), and pit the Personal CellSpot against our daily Wi-Fi setup.

The Personal CellSpot is actually an ASUS TM-AC1900 dual-band wireless router (about $199 through Amazon) optimized for T-Mobile’s network, and extends coverage up to 3,000 square feet; that’s more than enough for the average American home, and should be plenty for the typical small office, too. Our office is about 1,800 square feet, so the range had us covered and then some. The Personal CellSpot is a standard 802.11 a/b/g/n/ac router with four Ethernet and two USB ports, and it supports for 2.4GHz and 5GHz frequencies, and encryption for 64/128-bit WEP, WPA/WPA2-PSK, WPA/WPA2-Enterprise and WPS.

T-Mobile says you can use its Personal CellSpot either as a complementary device, or as our lone router. We used it in addition to our current setup, giving us the opportunity to test it against our current Internet coverage, which is pretty beastly (about 100 Mbps down and 20Mbps up, which is important for our line of work). After initial testing, we actually found that the Personal CellSpot outperformed the setup we use on a daily basis (Apple’s AirPort Extreme, along with a few AirPort Expresses).

When I say outperform, I mean the overall coverage area; the call quality was about on a par when on our office Wi-Fi, though we were able to stray further away with the T-Mobile Personal CellSpot. Chances are you won’t wander too far away from your connection, though it was impressive just how far the range extends.

We tested it using an iPhone 5s, though any new device sold by T-Mobile will support the free Wi-Fi calling feature—even the new iPhone 6 and iPhone 6 Plus. Calls, as expected, sounded great—a lot better than if you used T-Mobile’s normal cell coverage, which is fairly decent around our office in Irvine. If you have a phone with VoLTE support, calls will be handed off seamlessly when switching between Wi-Fi and cellular; when you do approach the edge of your Wi-Fi network, you should either get a pop-up notification or sound as a warning.

We didn’t congest the Personal CellSpot up too much with other connected devices, though a router like the Asus TM-AC1900 should be able to handle a family of gadgets without issue, and it always gives your phone calls priority over other connections on your network.

The approach here by T-Mobile is brilliant when you think about it. Let’s face it: the carrier still can’t compete with rivals like Verizon Wireless and AT&T in terms of coverage, so its new Personal CellSpot project effectively mitigates that while T-Mobile beefs up its network. Of course, you still might have crappy coverage in your little town, but at least you’ll be good in the comfort of your own home.

T-Mobile’s network has improved dramatically over the past several months, while its Un-Carrier initiative offers some amazing deals. The fact that you can use an expensive router in your home for just a $25 deposit is awesome, and it works exactly as advertised, meaning you’ll no longer struggle to get a connection in your house.

T-Mobile customers can pick up the Personal CellSpot with a qualified Simple Choice plan—all you need to do is go into a T-Mobile store or call the carrier to request one, and you’ll get the router with the aforementioned refundable deposit. In all, there’s almost no reason not to use T-Mobile’s new service. The coverage is amazing, the price of free is an obvious plus, and you get a great router out of it.