well, each to their own as they say.
I don't agree that it is just a Moka pot- as I said the machine has several technical and functional differences that preclude it from the moka class. In addition to the ones I already mentioned the machine also has two separate pressurised chambers- the boiler and the head... It may be tempting to label every machine that makes coffee on a stove a 'moka' pot but it is not accurate.
neither do I claim it is an espresso machine in the modern sense.
It really is a machine in its own class. I know it's not for everyone- and that it's not the cheapest stove-top machine available. The Sorrentina machine employs old techniques and materials in manufacture and is expensive to make. I personally believe it is the best looking stove top machine FULL STOP- and for frothing milk: I have never seen it's equal on a gas hob. It even beats the pants off my La Pavoni Europiccola in the frothing department.
On a side note: I am not sure about modern semantic distinctions concerning the term 'espresso'. The La Sorrentina machine produces real crema as you can see in the images above. When used correctly the shots are dark black, rich and thick + crema. The Crema may not be as thick or persistent as you would get from a pump or lever machine- but crema it is never the less. As I understand it the term 'espresso' dates from the turn of the century (around 1903) and simply means 'fast' in Italian. Modern definitions often have things like minimum BAR pressures for 'true espresso' production- but such pump and lever machines didn't even exist until the mid-twentieth century.
If we follow the modern definition of espresso- we should then be forced to say that millions of people who enjoyed so called 'espresso'
before the first Gaggia spring lever machines of the 1950's:
were all deluding themselves... I like to think that some of those early Italian Baristas were such masters of their art- that they managed to pull true 'espresso' shots-
before the lever machine was ever invented. It may be romantic and deluded... but that's exactly how I like it

. If you want to prove me wrong (and have a time machine)- by all means- take me back to Milan, 1926 for a pre-lever 'espresso'.
I am in like Flynn!