The first time that happened to me, was when I wanted to run my first test transaction at the command-line, and Stripe had generated the customized console commands for my specific app (with my specific API keys, etc.) and literally allowed me to copy and paste from their secure site to my command-line without having to do any thinking.
That was my first 'aha! OMG...this API is awesome' moment. There were many others, and the truth is I forgot until you mentioned it.
Now that you mentioned it, it reminded me how blindingly simple that is to implement - but SOOO many developers (I am guilty as charged too) overlook those little details that make SUCH a difference.
Why would I use it instead of PayPal, 2CheckOut, e-junkie, etc?
As a seller of software myself (http://www.devside.net/server/webdeveloper), I can tell you that "API is cleaner" and "lower fees than 2CO" don't do anything for me at all.
I sell software and subscriptions online; I'm working on the switch over the Stripe because I really appreciated their cleaner API and low fees.
I've been using PayPal because it's cheap and easy, but they screw up many foreign payments (that have worked fine when run through Stripe), the whole "eCheck" thing confuses the hell out of people, and that whole "no, you don't have to create a PayPal account" thing. It's just unprofessional.
I can set up Stripe to handle processing for me completely transparently, and still without passing credit card data through my servers.
1) Getting to set up and manage another new account.
2) The pleasure of getting to rewrite (and test + debug) my backend payment process.
3) Getting a slightly cleaner API (that I'm never going to see after I implement it).
4) Saving an extra dollar on every transaction (of a $125 sale).
5) Working with a relatively new, and in that effect, inexperienced payment processor.
1 and 2 are not benefits to me at all. 3 and 4 I don't care about because they are marginal at best. 5 is a killer.
So why would I use Stripe?
> I can set up Stripe to handle processing for me completely transparently, and still without passing credit card data through my servers.
Same as it is now.
> I've been using PayPal because it's cheap and easy, but they screw up many foreign payments (that have worked fine when run through Stripe), the whole "eCheck" thing confuses the hell out of people, and that whole "no, you don't have to create a PayPal account" thing. It's just unprofessional.
Without experience, Stripe will screw up even more. If not on this part, then definitely on other parts. It's just the way it works.
Nothing differentiates Stripe for me from the rest of the bunch and I'm not going to fall over backwards putting in more work to switch to Stripe just because someone says the API is cleaner.
Give me an actual benefit and I'll consider.