I have cruised as a Suite guest on the POA several times, and as a Haven guest on other ships. Yes you can ask the butler and concierge the same things. Yes the crew is mostly American, but not 100%. Our room stewards have all been foreign, and my most favorite butler was from Rhode Island! My parents and I are headed back to the POA this coming summer. It’s such a great way to see Hawaii!
As to your other question, I do see a difference in crew being American vs foreign. In my opinion, and I’m not stating this as fact, I feel that most American crew view their jobs as just that- a job. The foreign crew view their jobs as their careers. They are often providing for their families back home and take great pride in their craft. They are not going to risk their livelihoods at any cost. That being said, I think the grew is great.
The only ship that sticks out in my mind as having the worst crew was onboard the Celebrity Summit. We will never sail with them again.