The only way you're truly going to know if these guys are worth partnering with (aside from some huge red flags you didn't mention) is by partnering with them.

The only way you're truly going to know if these guys are worth partnering with (aside from some huge red flags you didn't mention) is by partnering with them. If they can't develop product and they can't sell, they're useless to a startup. That won't take long to suss out. Go all out, full marriage, full honeymoon. Have meetings as necessary. Work at it. The biggest problem with business guys is failure to close- either they don't put the time in or just can't sell. Give it three months, and either pat yourself on the back or throw in the towel. Repeat until you find a successful venture or have to get a job. One other warning about "two business guys". They tend to turn on each other more often than they turn on the tech guy. It's often sudden and unpredictable. Make sure you have that contingency covered in your formation documents.