Having worked both sides of the fence and now working for both sides of the fence I think i can say it ain't cut and dried.
Historically there was job security, it's certainly a bit harder to get rid of an individual in the public sector. But I left the public sector many years ago when it became clear job security was no longer a part of the equation. As for pay, when I left and went private I basically doubled my salary in 5 years doing the same job.
Now I see staffing in the public sector being trimmed, trimmed and trimmed again. But bloody hell, many of them are getting leaving packages and early retirement deals that I could only dream of.
As for pensions, I think it's rare to see a private pension anywhere close to being as good as a civil service one.
As for leave, there are still departments where you make sure you've taken your allocation of sick leave in the public sector. Whereas I don't take sick leave and I'm on call in the evenings, weekends and on holiday unless I make a really big deal about it. To the point where we now have a system of 'hard leave' and 'soft leave'.
I'm private sector now, doing a job that exists in both sectors. All in all, I wouldn't go back.