I have done both and loved (and hated) both.

Self Employed Pros

1. Freedom! You work as much as you like, when you like, where you like and dressed in what you like.

2. Money! A successful freelancer or consultant can make significantly more than the same job as an employee. And there are tax benefits.
I earned 40% more in one freelance gig when compared to the same work as a fulltime job.

3. Sanity! A consultant does not need to attend 8-hour department meetings, travel at peak commuting times, or get embroiled in a politics.

BUT!!!

Employed Pros

1. Security. You are less likely to be let go off because you are an employee. Cuts often happen with the freelancer. You also are being developed and are not usually judged on a single project like a consultant.

2. Future! As an employee in a good company you have a career plan, you have opportunities for advancement and you are around for the long term.

3. Control. As a freelancer you have to please your boss or your client. You don't usually make strategic decisions and you rely on other people to give you direction. As an employee you can become the boss and control your future.

Author's Bio: 

David Couper is a career coach and writer who for the last twenty years has worked in Europe, Asia, and in the USA with major organizations including the BBC, Fuji Television, Mattel, Sony, and Warner Bros.

He has successfully coached individuals at all levels including CEOs of major companies wanting a new challenge, frustrated souls wanting to make their dream come true, and front-line employees laid off and desperate to get a job.

David has published seven books. His works on interpersonal skills, counseling in the workplace, and management issues (published by Connaught, Gower, HRD Press, Longman, Macmillan/Pearson Publishing, Oxford University Press) have been translated into Swedish, Polish, and Danish, and published in the UK and the USA.

David has a degree in Communication, a postgraduate qualification in education, is certified in a number of training technologies, and has a Masters in Psychology. He is a member of the American Society of Training and Development, Society of Human Resources Professional, Writers Guild and the British Academy of Film and Television.

He has dual US/UK citizenship and speaks French and Japanese.

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David Couper, The Official Guide to Career Change.