Having worked for around 4 years in the private sector, it was nothing short of a delightful experience. I have accelerated my learning curve, accomplished interesting projects and got to see how politics (at all different scales) move things around.
Things move fast, demands keeps increasing, you are expected to deliver on time with the same 8 hours a day and a doubled up load year after year. Your time is often consumed beyond the official 8 hours, there will be days where your social life is dominated.
All the previous things may sound bad, well that depends on whether you enjoy work or not. If you do enjoy work, then all of what I mentioned is totally fine and you will have fun doing it. However, enjoying work is by no means an easy state to reach, there are a lot of factors, the nature of work itself (obviously), your colleagues, your management, the established culture, all of these get to decide whether you will enjoy your work or not, and that's by no means exclusive to private sector, but the public sector has other aspects to consider that may take precedence.
I have experienced good and bad management, which I see as a good thing. You don't get to appreciate good things fully until you have gone through the bad ones. I have seen management take decisions based on their hormone levels on a particular day, singling out individuals and major decisions that will affect years to come. I have also seen all of that shift greatly into an honest and rational management, that lasted until I quit.
My overall experience is great, I loved it and appreciate all the good times.
Moving to the public sector was not an easy move, and settling in was even harder. It means slamming your brakes hard, if you were working at 200 km/h then you will be at 20 km/h. Things are much slower, projects take much longer, people are much more relaxed.
It's really two sided, and it really depends on what plans you have set for your life (or have you?). If you are looking for a long term career with potential growth and consistent commitment from your end, the private sector is your culprit. However, if you are looking for stability between your work and social life, or generally speaking to own more of your time then the public sector is definitely better.
For me, it's establishing my own business and having a stable career to support me in doing that. The problem though adapting to the public sector's environment is going to prove tough for you if you got used to the private sector's life.
The key point is to know where you want to head over the long run, that will determine which choice to make; that's by no means an easy thing to determine, it took me months personally.