I just activated my 7 day trial and what ever testing I did ate all, 100MB data in less than 5 mins. Way too low to do any streaming. So I can't really see if it's as fast as T-mobile. What little testing that I was able to do, I only saw speed around 7Mbps to 9Mbps compared to T-mobile where I got 33Mbps to 60Mbps peak. All done though the Speedtest app. I've triple, quad, 5x check my data settings.
I do find Mint Mobile's pricing attractive but it's 5x slower than T-Mobile. Maybe it's a trial. I don't know. My status shows 4G LTE in a lot of the area and in some cases 4G LTE+.
Could you up the trial data to 1GB? Talk and text is fine but 100MB of data is really nothing.