Choosing by terrain and style of riding.
On road, there is no question a hub motor is a far better option. Roads and smoother terrain mean pretty much everything can be ridden over, quickly, quietly and with very little maintenance.
Off road, things become not so clear. If you have long steep terrain a mid drive is much better because you can choose the right gearing. This means no need to stop to let the motor and controller cool down and you use much less power to get there. The same applies for any terrain that doesn't allow going fast: single track with lots windy bits with obstacles. A hub motor would be constantly moaning at the low speed.
Then comes the really unclear parts. For rough bumpy stuff especially climbing up steep, where you can't let off the power or just want to blast through a shorter section, a hub motor is better because there is no powered chain dance. The heat won't be a big problem as it sheds it slowly on the next flat or downhill. There is no constant gear changing which slows down the ride too.
For downhill or any type of riding where there is no need for motor power or you want to pedal, there really is no question at all that a mid drive is far better, because there is no motor slowing you down (cogging) and the weight of the motor is centred, so sprung as much as possible between the shocks.
You could also choose by other characteristics you want
weight
If you want the lightest set up it will be a mid drive as they can be smaller motors achieving the same results (slower over all because requiring gear changing in general) and they require less battery to be carried generally. This could be an important factor because you might want to pick up your bike, or hop over obstacles.
Sound
There is no question that hub motors are generally a million times more stealth. Smaller mid drive motors require more reduction because they spin faster and a result can pretty much scream or in other words there's a higher pitch.
