Owner of a Nesspresso machine with Aeroccino (since 2017), so I will compare the machines. Firstly, both the Dolce Gusto and Nesspresso machines are from the Krups company and not from Delonghi (as far as I know, those who bought Delonghi machines ended up having issues over time, even with regular descaling maintenance every six months, which is very important if you want to keep your machine for years).
As for the build quality, it is sturdy but not as much as the Nesspresso, which has metal parts instead of plastic like this one. In terms of size, it is much more compact compared to the Nesspresso, which is a positive thing because it doesn't take up the entire counter. In terms of noise, they make the same amount of noise. Some people complain in general about the noise of espresso machines, but we should remind them that any compressor makes noise in order to create pressure for water flow.
Now let's talk about the capsules. We are definitely talking about a wide variety of beverages, such as chocolates, lattes, teas, French press, cappuccinos. However, I must inform you that you will have to visit different supermarkets because depending on the supermarket brand, they may not carry all the flavors I mentioned. So if you want to see the full range, you will have to visit different supermarkets. (I should mention that the machine comes with €2 coupons, totaling €40, so with each capsule box, you will have a €2 discount. Now, as for the variety of coffee, this is where Dolce Gusto falls short. Unfortunately, it doesn't have as many blends as Nesspresso.
Regarding the price of the capsules, I must inform you that Dolce Gusto's capsules are much cheaper than Nesspresso's (I'm talking about purchasing capsules either from Nesspresso itself or from supermarkets).
In conclusion, for anyone who wants a coffee machine (for Freddo Espresso, cappuccinos, and other beverages), I would recommend Dolce Gusto right away. On the other hand, for someone who is more knowledgeable and wants different coffee blends, then Nesspresso is the way to go. I forgot to mention that Nesspresso doesn't make beverages like hot chocolates, teas, etc., it only makes coffee.