I've been at a startup which made (and continues to make) nearly all of these, except for "don't do it with a founder you don't know well" mistake. It remains to be seen if they succeed, but they aren't really hurting either. Business is growing, albeit slower than they (or their investors) would like. Their secret? Two super-deep-pocketed customers that pay them about a million dollars a month each. Because of this steady revenue stream, it's also much easier to raise money. As Eric Schmidt (then the CEO of Google) used to say, "revenue solves all problems". The crazy part about this is, those customers came to _them_ because they knew a couple of prominent dudes who work there, bizdev was not involved.