I'd guess 98% of everything I've cut has been using Baltic Birch - mostly 1/4" with 1/8" second runner up and the rest 1/2".
And about 98% of the patterns have been Steve Good patterns (thanks Steve).
The wood has a uniform color. Cut easily, takes stain and finishes well.
Is locally available in various sizes, compared to hardwood.
The quality is better than other plywood available at the box stores (HD/Lowes).
That's my 2 pennies worth.