I build startups all day every day, so I'm comfortable with the field. I've got what I think is a good idea and a ton of execution on it so far. I have a small group of testers that (about 20% friends, the rest random strangers) and a desire to make a great product.
There is a great monetary upside potential, but I just don't have the resources at this time to quit and focus 100% on this. Of course, I sleep so very little that I spend at least as many hours "on the side" as I do at my day job, so it might be somewhat moot anyway.