Bet365 is a good affiliate program but is perhaps suffering from the fact that it is a popular casino and a lot of people are already members which makes it a bit harder to convert. The program do however still convert well and Bet365 offer more or less all types of gambling there is. (Affiliate share can very between different game types).
The BET365 products are popular for a reason and they offer good sites that are well worth promoting. Bet365 is a good primary affiliate program that can be used across all sections of a casino site. It is however best used together with a good affiliate program for a less well known and less popular casinos so that all those that already are BET365 members get targeted by advertising for a casino they might be interested to try as well.