many are pretty similar, some aren't very good. the condition is very important too because ceramics is really tough to lap.
there just isn't a current production so you have to pick from whatever's survived through the years which means you pays your moneys and takes your chances... for me it's worked to about 80%, i.e. 20% of the barbers hones have been junk. i just saw the other day one of them still sitting in a corner of my porch.