Benefit vs W7 dupes

On the market there are some great cheaper products, mainly W7, available as dupes for Benefit and other higher end brands.

So they look the same, the product is the same but why is the dupe 10x cheaper than the higher end product?

I'm comparing Benefit's Thrrrob powder and W7's Candy Floss (dupe for Benefit Dandelion) and Africa (a dupe for Too Faced Leopard highlighter).

One major difference is on the inside. The pan in the Benefit product fits snuggly into the case where as the pan on the W7 dupes is loose and a really bad fit (the Benefit product is on top in the photo below).

Another difference is that when I pulled the lid off the Candy Floss powder the container started to come away from the base. On Benefit products the container is attached to the base rather than just being stuck on.

The bases are also quite similar except on the Benefit product all the information is on a stick on label and talking of ingredients they are mainly the same for each product.

And the products themselves. Surprisingly the dupes are more pigmented and the Benefit Thrrrob powder but I guess the only other thing to do would be to see how long the dupes last. I've been using Thrrrob on and off for the past 2 years and have only just recently hit the pan. 

L-R: Thrrrob, Africa and Candy Floss.

So considering Benefit powders retail at £23.50 and W7 dupes for around £2.99 I would certainly buy the dupe product over the higher end product. Even if it doesn't last as long it's still a mega saving.

Have you tried any of these dupes, what did you think? Are there any others on the market that I should try?