I don't directly tell you which one is the best dice site, but via the following link to a website that collects and presents basic statistics on dice sites, you can easily find what you asked for:
https://dicesites.com/. It is clearly and undeniable fact that Primedice is the biggest dice site, in both three indicators: total bets, total wagered, and max payount. You can use graphs to see that fact (
https://dicesites.com/graphs). However, it depends upon each person purposes, if someone want to find a dice site on which he or she can invest, the things might become different, but you can (once again) find what you need on the given site above. In addition, detail figures of Primedice site are:
- Bets: 22,103,613,252
- Wagered: 2,247,894 BTC
- Max payout: 30.0 BTC