Honestly, I'd say PIPS and Studiotraffic and YMMSS are the top 3 stable, solid long term money makers. With studiotraffic, you get 1% per day on your investment and you get paid monthly. You also get 10% on whatever your referrals invest.
With PIPS, you get 2% per day on your investment (business days only), and it's ben very stable for a long time now. The comission is $10 per month on each referral you get which doesnt seem like much, but it adds up very quickly and turns into thousands of dollars later

YMMSS is good because it's been a proven system that has worked for a really long time. Everyone trusts them, and I havnt heard of any bad complaint about them.
YIWSN is just like YMMSS, but much newer, and hasnt stabilized yet. We will see if this one gets good in the near future.