They seem to be reliable, assuming you don't screw up on your order.
They do respond on orders that have gone wrong or lopsided. It is documented, whether the purchaser bother to respond back or not is not shown.
http://shoptemp.net/shop/usa-hot-stuff-usa-in-stock.html
Be aware that multi-location vendors will draw from any location if an item is out of stock from the purchaser's location matching one of the vendor's shipping warehouses. This means your shipping time can take more than 2 weeks if they have to draw from an out of country warehouse.
Unless you got a visa, my listing this site for you is on a very very very short list of vendors that take mastercard.
The only other people I have recommended this site for use so far were those that lived in Singapore. As to their purchase experience, they haven't replied back. I would have to take this as they got what they ordered in this case. As for being a scam, I would have already posted it as one in the second post if they were.
Be aware that a bad experience with a vendor does not always equate to being a scam.