Ben is looking for some help figuring out which direction to take is application. He’s looking for input from ISV’s, so if you have a chance help him out.
My 2 cents is to try and provide support for all of them. It doesn’t have to be all at once but you should have the major guys in there like share-it. Maybe them, Authroize, esellerate and another CC gateway or two. You need to have these because (in my mind) these are just necessary evils. They’re aren’t why someone like me would buy your product. It’s the other features that are the “killer” features. Follow up emails, advanced license management, customer self service. Those are the problem you’re solving for me not the gateway. You need to support whatever gateway I want to use so that I can purchase your product to solve my real problems which are excessive customer emails about licenses, manually creating email reminders, etc.
I wouldn’t worry about them being a competitor. There’s lots of room in that market, plus being a small biz yourself you’ll have alot more “street cred” if you market things right than they will. They’ll still outsell you 10000 to 1 but that doesn’t matter because that’s still more money than you need. Hey, HelpSpot competes with Intuit and their CEO owns a stinking Basketball team! There’s plenty of money for everyone.