johnnydoom The grind is important... It was so fine that my cheap Cuisinart doesn't have the pressure to run through reliably
The grind needs to be completely different on pressurized (rather coarse) and regular (very fine) filters. Most machines can work with both kind of filters altough the small 51mm ones are optimised to work with pressurized filters, the larger 58mm machines are optimised for regular filters. Capuccinos and lattes are best made with pressurised filters, the real deal espresso with unpressurised. If you want a versitile espresso maker that accepts all kind of filters look for 20 bar pressure or more.
Regular filter single layer with a lot of holes at the bottom:

Pressurized filter double layer with one hole at the bottom:

On those small 51mm machines one can also use ESE-pads (Easy Serve Espresso) with the right adapted filter. It's an easy way to start becomming a barista : right grind, right dose, stays fresh and most mayor Italian coffee brands have them. One can easely find such a filter on Amazon if it is not included with the machine. Downside for a double dose one needs to charge twice; there's no 2 cup ESE-pads/filter.
The ESE filter:

The coffee I use (0.15€/dose):

My machine Hkoenig 20 bar (100€):
