Compared to hub motors, one of the biggest advantages of the mid-drive motor is that it can utilize the bicycle's gears. The motor runs more efficiently at higher RPMs, and mid-drive motors are typically tuned to operate efficiently at a natural pedaling cadence. Therefore, when you pedal in the correct gear, the motor will run in its comfort zone.
All of this means that, under the same power and torque conditions, assuming you shift to the appropriate gear, mid-drive motors will typically climb steep hills better. The ability to work with your gears has other benefits, such as improving range, and it contributes to a more "natural" riding experience for most mid-drives.
In addition to climbing hills, hub motors cannot be used with most internally geared hub wheels, which are often a popular choice for e-bikes because of their low maintenance cost and ability to shift while stopped. This also means that if you want to use a more durable belt drive and still have gears, you're out of luck (unless you buy one of the rare e-bikes with a small gearbox).
Because mid-drive motors run more efficiently at higher RPMs when used in conjunction with a bicycle's gears, they almost always have better range than similarly powerful hub drives. This is especially true when comparing a mid-drive motor with a torque sensor to a hub drive without one.
As a heavier rider, this difference is already quite noticeable to me. Interestingly, on a 500Wh battery on a hub drive e-bike, I can typically only get about 30 miles of range, while the same-sized battery can provide me with similar power for 40 to 50 miles of mid-speed riding. In low power configurations, some mid-drives can even achieve over 60 miles of range, which is entirely feasible.
But again, there are some subtle differences here; torque sensors on hub drives will narrow this gap to some extent, and it is much easier to find a hub-drive e-bike with a 600+ Wh battery than it is to find a mid-drive with these specs. Of course, choosing a larger battery will add weight, and this can make things very inconvenient if you run out of juice.