It has a faster theoretical peak throughput. So, from a practical standpoint, if you are in an area with good 4G coverage and at a time when network congestion is not an issue, you may see a noticable difference in speed; however, if the speeds you are seeing on your current hotspot are signal or congestion related, then you may not see any difference.
I thought I was add some additional information to this aspect.
The T-Mobile network side, the device can go much faster.
The WiFi radio side the speed is approximately the same as the T-Mobile 4G Hotspot (MF61)
The Sonic can be connected by USB to your PC, this bypasses the WiFi radio and higher speeds can be achieved.
Speed will be affected by signal quality, network capacity, stuff on your PC....your mileage may vary