Have you tried or considered lago? (getlago.com) I haven't heard of killbill, so will definitely look into them. Love that they're open-source as well and seems like they've been at it a long while.

Thank you! First I hear about either of those, but definitely interesting. Are there paid / hosted versions of lago? after a sub-par experience trying to switch to ChargeBee I'm looking for alternatives, but struggle to find something that fits our needs.

Yep there is a paid / hosted version of lago; I believe you can book a demo of the hosted version from their website and get a good 1 on 1 with one of their developers so you can see if it works for your needs.

Lago looks interesting, and promising if development continues, but nowhere near as feature complete or battle tested as Kill Bill.

Lago looks beautiful, thanks for sharing!

I will definitely look into that.