I was self-employed for ~3years then went to work for one of my clients for a year and now next week will be happily self-employed again and my boss will be a client again.
Anyway here's my 2 cents......actually this is what my wife tells me to do when I have an tough decision to make.
Make a pro's and con's list of going for it. Just make sure that when you evaluate the list $money$ gets less weight then job enjoyment/satisfaction. Of course it has to pencil out finacially.
If it's a go, set yourself up for success. Go to the local colleges, SBA office, SCORE (bunch of retired biz people), entreprenerial clubs, your lawyer, your accountant, friends with businesses, state biz license office, etc... and pick there brains for advice, resources etc... in setting up a biz. There are different biz structures, soleproprietor, LLC (very interesting), C corps, S corps, partnerships, etc... There are different ways to do the books. There are different kinds of insurance you need. Where will the biz be located. There are many things to take care of in setting up a biz. If any of these can be done while your still employed do it, because your biz will not generate any direct revenues from these tasks, in fact they can cost you some big $$$. This is sweat equity!
And please have some money stuck away to pay yourself and your biz costs for several months. Even if the terms of the contact have progress payments, you can expect at least 60 to 90 days from when you do the work until you get paid.
Whoa, somebody better pull me off the soap box.
I guess the answer to your question....yes I am happy and when I went back to being an "employee" it was not satisfying.