If only...
I've done private, public, and non-profit work, and I've done consulting work.
1. Private pays good, often, but if varies from industry to industry and boss to boss. It's also impossible to really compare pay between different offers because there is such a huge variance in benefits (another number it's almost impossible to get before you start). You might get a ballpark number from the interviewer, only to find out it is for single coverage, and you need family. I've seen variances in the 15% to 20% of salary.
2. public lower pay, little room to advance, no respect. There are alot of people working incredibly hard, and IMHO, no more slackers then you see at any large company. I do see a greater tendency towards fiefdoms. Job stability can be better. Benefits are largly the same as other industries, maybe a 7.5 hour day or a bit better pto.
3. non-profit Serious cronyism issues, alot of waste (in established non-profitss), low pay, no advancement. You might get to make a difference in the world (probably not).
4. consulting Your job makes money for your bosses, so pay is better. Otherwise, the same. Often there is less stability, but not always.