i have had a Tassimo for a few years now, it works well, I normally use Kenco columbian or the Americano, I do not normally buy ones with milk. i see they have some new ones on their website, which I have not see in the shops , like Gevalia Ebony.
You can add more water by pressing the start switch and keeping it pressed after the operation.
i also have a Dolce Gusto, again, no problem with the machine, depending on what you get the coffee is nice.
The problem with these pod machines are the price for the pods, they are not cheap, which is why I only use them if i can not be bothered to use the espresso machine.