Ok,
Are they basically the same thing as Huel?
No they are very different from Huel due to multiple reasons.
a) Ingredients.
- Maltodextrin. A complex carbohydrate with very high GI (85). This means that it will have high impact in your blood glucose that will cause a rapid increase (basically similar to sugar and the opposite to a complex carb). On top of that, it is just a processed ingredients that only gives you carbs. Huel and other brands tend to use oats or similar, which are a matrix of nutrients. They contain complex carbs, protein, fat, and vit&minerals. Why do they use Malto? It is more soluble, makes for thinner shakes (easier to drink), doesn't have taste (unlike oats), it is very energy efficient, it is cheap.
-Sugar. 19g per 350 serving (well over the recommended) You will not often find this on Huel or other shakes, since they try to keep sugar at a minimum.
-Corn oil. Not a great source of fats.
b) Objective of the shakes.
Ensure and similar products tend to put taste over nutrition (higher likelihood of people sticking to it).
Probably just trying to get maximum calories into you so you don't lose weight while you're ill. Sick people often have poor appetite and don't eat enough.
This is a very good point.
c) Different market.
As pointed above by Steampunk; I think both brands target different audiences. Looking at Ensure products, they are all 200-350kcal ready to drink shakes. Huel's serving is 400kcal and it comes in powder (yes, there is an RTD product too, but the main is powder). You need 5 Huel's to reach 2,000kcal ("average" person recommended intake). With Ensure you will need a bunch more.
I feel like the last two points I've made are a little more abstract, but I hope you understand the gist of it.