How much is larger amount for you? It can be vary from different perspectives. Lets say 0.1BTC is a large amount already for some people but it can be something small for some other people. If you are asking about the daily race, yes they have it and there is no one complaining about it so far. It means that the races are real and paying the winners. You may try try yourself with few hundreds/thousands doge to test the race and wager as much as you can to be eligible for the prize.