I would stay away from this site for now. In their FAQ they have an explanation of their "provably fair" system, but I can't find anywhere on the site where you can actually verify the rolls for yourself. Just saying that you are "provably fair" doesn't make you provably fair.
I like the simple design and I like the fact that you can gamble with a number of different crypto-currencies, but I'm not going to try this one out until they are actually provably fair. I recommend that others do the same.
We are provably fair, to verify a roll just look at this PHP script;
//We basically create HMAC using server seed and client seed with nonce (separated by ":")
$hmac= hash_hmac('sha256', $serverSeed, $clientSeed.':'.$nonce);
//Then we take the first 5 characters
$lucky = intval(hexdec(substr($hmac, 0, 5)));
If the lucky value is greater than 9999, we take the next 5 characters and so on.
Hope this explains it better. We will add a verification tool to the site soon!