Doesn't usually work -- the pot (amount of soil) is too small for the size of the tomato plant and then it is always dehydrated. A dehydrated tomato does not make tomatoes, because it is too busy just trying to survive. And with the pot size that comes with those upside down hangers, your tomato will never have enough water. Put herbs in your upside down pot instead. That does work. Or else some kind of low water succulent.

I have grew one years ago, just for the heck of it. I made my own pot by drilling a hole at the bottom of a 5g bucket. I planted a cheery type in it. There are many technical problems: I did get no more than a handful of tomatoes off of it.
The fact is NO PLANT will grow upside down in the nature. Cascading is not the same as upside down. Actually planting some cherry tomatoes in a good size hanging basket can be more decorative than upside down. Pick a small indeterminant cherry.

i've done it a couple of times, some success but yes there are problems as alluded to above. Wouldn't do i again unless there was a space issue.

One problem is when watering the water runs out the bottom and all over the plant making it all yuk.....so if you are going to do it, i would suggest growing it out the side of the container rather than the bottom.