It's nary impossible to judge founders, even investors are not very good. I think that 'heat' is probably the best way to judge: if they are growing, they have

It's nary impossible to judge founders, even investors are not very good. I think that 'heat' is probably the best way to judge: if they are growing, they have a good product, customers like it, and they're not paying substantially more for customer acquisition - and it's a large market - then that's a good sign.