https://www.t-mobile.com/cell-phone-plans
The Canadian networks are “better” because every Canadian rations their usage. I’d wager that Canadian networks are wayyyy underprovisioned compared to even the crappiest US network.
Check out the top div on that page, you'll see they conveniently want to sign up both you and everyone you know to qualify for that rate. I priced it for a single line in both the US and Canada. With that in mind TMo is a huge outlier in the US, too, and John Legere is responsible for singlehandedly dragging AT&T and VZW kicking and screaming into the 21st century of pricing over the last 5-6 years.
They also have far and away the worst network in the US, trust me, I've used them for years -- and love them. Their network is still hot garbage though. Frankly the best TMobile network you can get is when you roam onto Rogers, Bell or Telus in Canada.