I think no need to suggest because it's also a known website which has been existing for a long time. If you have been making good amount with their referral system.
I guess no need to look for any other and just focus there.
I am sure that there is at this forum a good list of top referrals programs where people can choose the best one for them, It would be cool to see it, haven't searched for it yet, maybe someone here already knows the thread.
It will be interesting to know the top one in all aspects of rewards to their supporters.
Ok, if you think that there's a better one, keep on looking out but as I've said I think you already have a good one.
Hangout to the Gambling section and look for the casinos which you think you can market to get referrals just like the strategy that you've done with your current one.