Johnny: End grain boards have the advantage that knife cuts are made - well - into the end grain. Other wood grain orientations in a board will have the knife cuts made across the grain. Over time these across the grain cuts do 'wear away" the wood.
That said - I have many cutting boards - and none have been end grain. If boards are so well used that they show knife cuts as wear, well, I guess I like that.
Put simply - make the board(s) in any grain orientation that you like. It still works as a cutting board!
Henry