It depends. The phone is capable of fantastic speeds, but your "speed" is determined by a number of things:
Proximity to tower
signal strength
congestion of the tower
backhaul of the tower
network provider
any deprioritization that may apply to you
I'm on T-mobile as well and even on old fashioned LTE, I get between 25mbps-267mbps download speed. It is just super dependent on where I am and what is going on.