I have looked at several vintage BU's
I haven't used my Necchi BU (Original BU) for some time and it was one of the first vintage machines in my stable. I swear it uses low shank feet. It came with a few and I used them. I will have to get it out and check.
My collection increased without any organization and my feet are all mixed up. So, I consequently know when someone says they prefer to stick to one type shank. Since, I've learned to keep feet with machines.
And, you are correct. It is a silent beauty and sews extremely well. However, I'm hooked on the SS vintage Singers (hard to explain).