I had two different Tassimo machines and both went wrong. I've also used a Dolce Gusto machine.
Personally I think Nespresso is way ahead of all of them if you want a decent coffee, its about as close as you can get to a freshly ground espresso without actually doing so. The downside is that Nespresso capsules are the most expensive and are only available from their outlets and online. They also only do coffee, where as the other manufacturers tend to do teas and various coffee drinks using UHT milk.
I used to use a proper coffee machine, but found that because of having to warm it up, tamper the coffee, make the drink and clean it all up afterwards that I was only using it really on weekends. Using one of these machines, I can get a decent coffee quickly with no mess every morning.