With Facebook’s initial public offering growing closer by the day, information about the company is being sought from every possible angle, and online jobs and career community Glassdoor went straight to the most knowledgeable sources of all: Facebook employees.

Glassdoor gathered thoughts from workers at the social network on topics including overall satisfaction, salary packages, confidence in Co-Founder and Chief Executive Officer Mark Zuckerberg, pros and cons of working at Facebook, and even the interview process.

The highlights from the findings by Glassdoor include:

Employee satisfaction: Glassdoor has tracked Facebook employee satisfaction since 2009, and it has been a roller coaster, albeit consistently high, rising from 4.4 out of 5 in 2009 to 4.7 in 2010, before slipping to 4.2 in 2011, and then rebounding to 4.6 thus far in 2012. Employee morale and work-life balance ratings followed similar patterns, while the company’s compensation and benefits rating remained consistent, for the most part.

How’s Zuckerberg doing? Zuckerberg’s approval rating followed the same pattern as employee satisfaction, rising from 86 percent in 2009 to perfection in 2010. With nowhere to climb to, it fell to 88 percent last year, but it has bounced back to 97 percent in 2012 so far.

Positive aspects of working at Facebook: The way to a Facebook employee’s heart is apparently through his or her stomach, as more than 25 percent of employees cited the food as best reasons to work at the company. Other notable responses included:

  • Benefits (17 percent)
  • Perks (12 percent)
  • Salary and compensation (10 percent)
  • Sense of innovation (5 percent)

Needs improvement: Long hours was the most mentioned negative issue with working at Facebook at 10 percent, followed by work-life balance difficulties at 7 percent, and company politics at 5 percent.

Check, please: Average salaries for some positions at Facebook include:

  • Product manager: $130,143
  • Research scientist: $123,308
  • Business development manager: $115,000
  • User operations analyst: $43,518

Tough interview: The interview process at Facebook has steadily become more difficult, rising from 3.0 in 2009 to 3.3 this year, and Glassdoor added that 44 percent of interviewees reported negative experiences, while just 6 percent reported positive experiences.