I prefer to cook it . Why would you blend soup in a blender with its container? It's highly unpractical.
Even if you want to make something like tomato soup or zucchini soup you have to cook so this is the best option for it:
That way you can blend and cook at the same time.
This question was answered a few times here. Most reviewers prefer Ninja.
Best blender ever! It comes with a recipie book for different soups, ssuces, drinks, etc. that you can make in in. I love my Ninja!