I'm not an employee, I don't have to pretend to care about career advancement and I get paid for the time I'm here. The money is actually better though I have to sort out my own pension provisions etc.
And I don't ask anyone's permission for anything, because they're my clients, not my manager.
Also, you aren't involved in office politics and you can upwardly delegate any decisions that you don't want to make ("I'm afraid I'm just a contractor, you'll have to ask my manager about that).
As a developer, I really get to get my head down and work hard, which is what I most enjoy about this job.
Out of interest was it difficult to start (get your first gig)?
YMMV. If you're in London it's probably pretty easy. Elsewhere you'll need to be financially prepared for the odd two-three month hiatus.
Need me to work overtime? Pay me.
No delusions about if the company is going to be acquired/give bonuses/advance your career.
Demand what you're worth, leave on time, and never receive an after hour request (because no one wants to pay your over time rate).