Check out this 6 Bitcoin bet!
It is one of the best and most of the players are kind.
Back when I was still playing there some of the players would have some fun in the chat and tip other player.
While stake reached it's 4 billion bets, as per title PD has made 29 billion bets and that's no joke.
Other sites have more bets but less high rollers.
The success or ranking of a dice site should never be compared to the amount of bets. There are many reasons for this. One reason can be that sometimes they have promos like "On the 10th billionth bet, get 1 BTC", etc and this introduces massive amounts of bots flooding the site and doesn't really create much productivity to the site.
A dice site ranking in my opinion should be calculated by the amount of bets X bet size and aggregated as a whole. So if someone makes 1 bet for 1 BTC and another site has 100 bets for 0.01 BTC each then they would be of equal weight.
To make it more accurate it can also be calculated based on the sum of USD bets since the price of BTC fluctuates too much. So basically if a site had more bets during the $200 BTC days it would appear they have a higher rank than a site which had less bets during the $20000 BTC days.