A semi automatic machine with dual boiler is generally the best performing followed by a heat exchanger single boiler (HX) machine if you’re regularly steaming milk and pulling shots together. If just pulling shots a single boiler dual function machine will do well, but is frustrating to use for milk + espresso drinks. I’ve had many machines over the years and am happy to answer questions. That said after a lot of years making espresso drinks at home I now prefer the simplicity and flavor of pour over coffee.