As I understand it, the bar pressure of all pump-driven espresso machines are effectively commoditised. Which means that no matter what machine you get, you are going to get a similar or identical pump.
Hence, when buying an espresso machine, ignore the pressure ratings. They are immaterial. Perhaps the best domestic espresso machine in the world is the Rancilio Silvia. Owning one myself, I can certainly vouch for its reliability and consistency in producing exceptional espresso. It isnt cheap though, bordering on AUD $800 last time I checked.
Here are some websites to start you off on your research into high-grade domestic espresso machines:
I wont say any more for now, as I suspect that most of your questions will be answered by the above websites.