I have used many varieties of coffee machines. I do have a nespresso machine amongst them, and it seems to work quite well. The volume of espresso/coffee it produces is low per unit time of water running through the coffee though.

When I use a normal espresso machine, with my own tamped grind, it puts out espresso/coffee at a higher rate, and I find it is smoother/less bitter due to that.

I do tend to prefer a less strong cup, so for me it is nicer to use my own grind as I can vary:
1. The quantity of ground beans 2. The fineness of the grind 3. How much coffee I get by how long I pull it. ( I realize running it too long will make it bitter )

In the article I am gathering he is measuring what percentage of the "grind" is removed in the process of brewing?? It would have been nice to see this compared amongst a variety of machines, not just 1 nespresso machine and 1 manual drip. Also an acidity test of the resultant coffee would be neat.

For the interested, here are the various machines / methods I have used:

1. Standard junky drip machine ( yuck... )

2. Bodum dual glass bowl vacuum
I find this to be the strongest method of brewing, but it also makes the coffee way too bitter for my tastes.

3. Keurig machines
Have used 5 or so different ones of these. The higher end commerical ones tend to be a little better but mostly they produce weaker coffee and let a lot of grounds through into the coffee. I don't think the water is hot enough from these, nor is the pressure high enough to get crema of any worth.

4. Tassimo machine
This is my favorite taste thus far. The programmed t-discs allow the setting to be varied ( heat and brew amount ), and has produced the smoothest coffee I've had of all the machines I have used. I own 2 of these machines. My only complaint is I cannot use my own grind.

5. Senseo
This is my favorite machine overall. The pods are small cloth bags, and the pressure seems to be high enough to produce good crema. Also; I can use my own grind in reusable filters that go in it. Great consistent taste and very easy to use. Also; very easy to clean the whole machine. I own 4 of these. ( for extra parts )

6. Starbucks "instant" machine. One company I worked at had a huge automatic like starbucks branded machine. This thing tasted horrible. The coffee was the most bitter I have tasted from any machine. It also tasted like it was never cleaned and had a high amount of grinds left in the coffee.

7. Super automatic espresso machine. Another company I worked at had one of the various $5000 automatic espresso machines. Unfortunately I forget the brand at the moment. It worked well, auto grinding etc. I used my own grind with it also. This was nearly equal to the taste/quality of using my own espresso machine, but I could not vary the tamp pressure. The auto internal tamping seemed too loose so the coffee seemed to have a bit less crema. It was convenient as it had less cleanup though.

8. Capresso EC100
This is my go-to machine that I use for my daily coffee. It is just a basic espresso machine. No real thrills here, but it has adequate pressure and heat. I grind my own beans to my desired fineness, add my own amount of beans to my taste at the moment, and typically brew like 4 shots worth out of the same tamped unit. This would seem to cause it to be more bitter but it does not and produces lots of crema. I also often rip open free keurig pods from work and use them in this machine. It improves their taste over keurig machines by far.

9. Old style large reservoir steamer with huge spring/lever.
I picked one of these up from a yard sale. Takes forever to heat up. Needs to be cleaned constantly. Feels very finicky. I am way too lazy to be able to get anything consistent out of this. Far too much effort for little gains.