I bought a 66% het pied from a friend but she has strong markers so I felt the risk was worth it. However she was just big enough to try breeding this year so hopefully I'll be able to let you know if/when she has babies hatch on my odds.
The hearsay I have is het pieds with markers prove out. Haven't heard of any that haven't proven out yet. Key word being 'yet'
(just read the rest of the thread so what I had to say has already been said ^-^; )