But pull a shot from a properly warmed-up, well-tuned BZ99S. You will taste the difference. The thermal stability is absolute. The crema is thick and hazelnut brown. The manual lever gives you a feedback loop that no app-controlled machine can replicate.
The E61 group is a thermosyphon, meaning hot water circulates through it constantly. In a home environment, this often leads to overheating the group. Before pulling a shot, you must perform a "cooling flush"—running water through the group without the portafilter until the sputtering stops and a smooth flow emerges. This is non-negotiable.
Descale is not optional. Because the boiler is so large, scale buildup will eventually kill the heating element. If you buy a used one, be prepared to open it up. Also, the toggle switches are rated for 15 amps, but they fail after 15 years. Replacing them requires a soldering iron.