I don't wear any of the minimalist shoes, but I will comment on the ballet flats.
They are not so comfortable for some people (like me) and can cause foot pain and other issues, especially after standing in them for a long time. I had to throw mine away. Flip flops bother me, too. I need cushioning.
Not a problem, as I generally wear shoes with a small heel if I am not wearing athletic type shoes or sandals.