Here is something from another board.
They talk very frequently how so many novice slate installers totally destroy an entire structure by not having the required experience.
Ed
Message reply from another board from about 6-7 months ago:
"I tried to buy VA slate from the Virginia Slate Company. They sell only imported roof slate, but they will not tell you this. In fact, I believe they intentionally try to mislead potential buyers into thinking they sell domestic roof slate. For instance, they brag about their quarries in Va, but will not tell you that they do not mine roofing slate from those quarries. Just ask if you can pick it up at the quarry.
You can buy VA slate from Buckingham Virginia Slate Corporation (a different company with a similar name), but I have read not so good things (on this board) about the current slate they are quarrying.
It also costs more than other domestic slate.
I finally decided to buy Vermont slate, where it seems to me there is enough competition and supply that a cautious shopper can get a good quality product. The price is cheaper and the slate is beautiful with more color choices. I bought thicker slate from VT and feel good about the prospects for longevity. (I'm certain it'll outlast me!) I bought mine from Camara Slate and I'm happy with the product.
I've heard that the going rate for an installed slate roof is $1000 to $2000 a square, but the quote I was given was a lot closer to $2000 than $1000. A year or two ago, Vt slate was just under $400/sq (just materials) and Va slate was over $500."