The brass in most high end heads slowly leaches lead into the boiler water. Arguably, this doesn’t matter at a coffee shop, since the boiler turns over the water in a few hours. At home, it takes a month or so.
Anyway, I settled on a Flair Classic lever machine (one moving part, all stainless steel and silicone gasket on the water contact path), and previously, a PID kettle.
It turns out that water boils at espresso temperature at ~ 2000 ft, so when the PID kettle died, I replaced it with an antique enameled cast iron kettle (my induction range heats it up ridiculously fast).
I boil the stainless espresso machine head in the kettle with the espresso water, which achieves the same thing as continuously circulating hot boiler water through it in commercial espresso machines.
I put the money I saved on the machine into a small commercial-grade burr grinder (like for the decaf beans at a coffee shop).
I haven’t noticed any consistency issues vs. a $3500 machine at work. That thing can crank out four espressos in parallel all day long, but I don’t need that at home.