Well since I got both machines myself I can do a compare type of thing.
The Dolce Gusto was the first machine I got about 3 years back, the coffee is ok as long as it is black, the chocolate is not bad. the milk pods are powdered and while they do a ok job they are not great and sometimes i find the drinks like lattes can have a after taste.
Machine is manual, so you got to make sure you start and stop it at the right time, not like I did when I first had it and left it running until I realised it is not going to stop
The Tassimo as I said before I only got a month or so ago, maybe two, it is more of a drinks machine than the dolce gusto as going by the pods will tell you.
Drinks that uses milk seems to be better, maybe because it uses liquid milk, but it is still long life milk.
Coffees are pretty good, not better or worse than the dolce Gusto, just different. Better range on the Tassimo.
Tassimo being semi-automatic is nice as well.
Price of pods is the problem for both machines, i been trying to find them cheaper elsewhere, but as of yet have failed, we don't have a costco
I love my coffee, I drink far too much, having one now before bed,, I prefer my espresso machine, but the pod machines are quicker.
I am glad you decided and I am sure you will love the coffee if you can afford the pods.