Growth thru Referrals - what tool do you use?

What tool are you using for referrals & rewards programs?

I am currently looking for the right tool to roll out a referral program for my Scrappy MarTech newsletter. I cannot find one that meets all of my needs just yet. After the basics of handling tracking and managing the custom rewards program & referral links, the requirements are:

• Be able to use my own landing page for subscribers
• Integration with AWeber so I can include the unique referral link in the email, with messaging on "you have referred y friends. you are x away from the next reward"
• Not require signing up separately for a rewards program. Too much friction.
• Zapier integration (I hate closed systems)
• Leaderboard and gamification

Here is what I have looked at so far:

sparkloop - Has everything I want except doesn't integrate with AWeber. They are targeting end of Jan/Feb for this.

viral-loops - Currently you have to use their subscriber form, They are targeting sometime in Jan to allow you to use your own form.

referral hero - Requires signing up for the referral program in addition to subscribing to your newsletter.

@yaroslawbagriy The Newsletter Crew has one coming out in mid/end January called ReferralKit for newsletters.

Anyone have any other referral tools to recommend?