I use Chargify and have been happy enough with the decision. It seems to me they are the best of the choices available, although definitely not perfect.
I wouldn't have rolled my own system though, not just the time to get it up and running, but then the time to maintain and improve it as time goes on. With a system like Chargify, subscription billing is all they do, so they add new features and improvements which you get for no effort down the track. With your own system, nothing improves unless you do it.
As for my experience with Chargify:
- It was quick to get subscription billing up and running
- Good customer support
- They are now adding new features regularly (I suspect since the recent funding boost they got)
- Good set of features (including flexible tax support which was important for me).
- Average documentation
- Average/Out of date examples
- Missing some fundamental features I would expect (reporting is very ordinary without you doing your own)