I used to have a reusable filter for my older machine. The top popped off, you filled it with coffee, and you put it in the machine. 

Now I have a K-Elite. I literally had to remove a piece of my brewer to use this. If I want to use a standard K-Cup, I have to put that piece back in. The filter itself is also the most annoying thing because it’s like a filter within a capsule with a cap. When you go to put coffee grounds in it the 3 pieces separate, so you can just scoop up the coffee. You have to take the whole thing apart and fill the inner filter, put that inside the plastic piece, then put the lid on. 

This whole universal thing, is lazy. I shouldn’t have to take pieces of my coffee maker off to use something that’s “universal”.  Do it right and make one for each brewer. Should be as simple as pop and go.