The best company to work for in the U.S.

Free gourmet food, generous time off and shuttle bus rides to work will buy you a huge amount of employee goodwill. Those are just some of the benefits that vaulted Google (GOOG) to the top of Glassdoor's list of the best places to work in 2015.

This is Google's first time in the No. 1 spot, even though the company has offered its legendary perks for years. One reason the company may be the favorite now is because it has been extremely responsive to employee needs, particularly as its workforce ages, said Robert Hohman, Glassdoor's chief executive and co-founder.

"They're a mature company," Hohman told CBS MoneyWatch. "They've been at this 15 years. Their workforce, which was probably largely twentysomethings at one point, is largely thirtysomethings or fortysomethings who now have families." The company offers generous maternity and paternity leave and childcare options and even helps pick up the expenses for diapers and formula for new parents.

The tech sector is famous for doling out employee perks to attract and retain workers, but many companies on Glassdoor's survey operate outside the tech arena. The top 10 companies on this year's list include Nestle Purina, Chevron (CVX), In-N-Out Burger and the Mayo Clinic.

One of the common themes noted by employees of those companies is the ability for their work to have an impact, Hohman said. They also enjoyed working with exceptional people. In-N-Out workers raved about their opportunities to grow professionally and learn management and organizational skills that will help them throughout their careers. Employees also praised flexible hours and a wage that's typically higher than average for the fast-food industry.

Glassdoor's annual survey, now in its seventh year, is based solely on the feedback from employees who participate in the company's online review process. The company also announced a separate list of the best small and medium companies to work for. The Motley Fool topped that list, followed by Fast Enterprises, Evolent Health, Intacct Corporation and TubeMogul.

Twitter (TWTR) was missing from this year's list after ranking as the top tech company last year, Hohman said. Though the company is still rated as an above-average place to work, it has seen some turnover in its executive ranks following its November 2013 initial public offering.

"It's not that uncommon for a company in its IPO year to have this tremendous halo," Hohman said. "It's very challenging to keep that going in the year following the IPO."

Hohman also said that this year's top 50 list includes by far the most diverse lineup of companies by industry in the survey's history. It's a reflection of a broad recovery in the U.S. economy, he added. "As the economy has recovered, competition for talent has gotten tough," he said. "Companies are having to get more aggressive in the perks and benefits they provide employees."

Here are the top 10 companies ranked on Glassdoor's list of the best places to work:

1. Google (rating: 4.5 out of 5)

2. Bain & Company (rating: 4.4)

3. Nestle Purina (rating: 4.4)

4. F5 Networks (rating: 4.3)

5. The Boston Consulting Group (rating: 4.3)

6. Chevron (rating: 4.2)

7. Supermarket chain H E B (rating: 4.2)

8. In-N-Out Burger (rating: 4.2)

9. McKinsey & Company (rating: 4.2)

10. Procter & Gamble (rating: 4.2)