What do you like best?
1) Merchant of Record - all taxes, compliance, etc, and any order disputes, they handle it
2) Simple competitive billing plan
3) I can get by with a very minimal site on my end (or I can make a complicated site on my side and use their API's)
4) The free, generous online documentation, and the sense of being welcomed as a customer. I looked at a competitive service which required that I go through an on-boarding process before I could even look at their documentation, and walked away from that.
5) Their support is very good; professional, knowledgeable, friendly,
What do you dislike?
I'm an experienced user of many types of software. So I'm picky. There are a few minor features with FastSpring's newer Contextual platform that I wish they had. However, Contextual is significantly better than their Classic platform, and I was happy with Classic. Their support bobbled a little when they were acquired, however, it seems to have snapped back. Their platform has a wealth of features; I'm probably only using 1/3 or less of what it is capable of. Nothing to complain about there!
Recommendations to others considering the product:
Think about the full workload required to do subscription management, and consider how much of that FastSpring can take off your hands.
What problems are you solving with the product? What benefits have you realized?
I needed a subscription billing front-end for my SaaS application. They do that all for me. Subscription management is the absolutely most complicated and difficult piece of systems analysis and design that I've ever done (I'm taking decades of IT career). After I figured out how the business rules should work, I was able to implement everything I needed using FastSpring. Their support team was critical to that success.