I have been an entrepreneur and a consultant, and I personally feel I am fair to middling at both. But I have seen some good ones, and have a few observations in the noggin archive.
There is a fundamental difference between the two, which relates to their target audience. It is all about who they have to please.
In general, the entrepreneur has to please him or her self, and his/her customers, but primarily strives for the former. There is a focus on the task at hand, and that effort leads to bias. They convince themselves their direction is correct, and they often fail to adjust before they are in need of help. Their vested interest in the venture acts as a blinder.
If the entrepreneur has a board, spends a lot of time listening to them, and takes recommendations in stride, some of this bias can be checked. If they don’t push back on their board when they have very strong convictions regarding a course of action, then they are weak, and should go into the consulting business.
The consultant on the other hand, has neither a vested interest (and if they want to be successful) any bias. The best of them can assess a situation based on empirical data, provide a succinct list of recommendation, and then wait for a decision. In some cases their compensation is based on some gauge of success, but most often not.
If the consultant wants short term success at the expense of the long term, they will kiss their clients’ behinds, and wait for their paychecks. These are the consultants to avoid. If you are an entreprenuer, and realize you need help, the last thing you need is someone to agree with all your false thinking.
The most dreaded combination is the ultra-biased entrepreneur and the butt-kissing consultant. This is a receipe for disaster. If you are lucky enough to find this combination in a public company, where the founder is still running the show, you can short the stock and make a bundle!