Even investors who thought U.S. companies would finally start hiring this year have been right royally disappointed so far, particularly if they bet on the companies that get paid to match workers with employers. The depressing fact is that they should have bet on jobs in China.

51job Inc. (JOBS), a major headhunter and jobs poster in Shanghai, has been the darling of the staffing industry for investors on this continent. Its share price has doubled in the past 12 months and is up about 355% over the past two years.

Compare that result to the returns of major U.S. agencies, whose own China operations could nowhere near make up for the losses in domestic work. Most of those shares are still well down, having rarely given investors reason for hope since hiring collapsed in 2008. And, as YCharts has noted in the past, the business model of the major temporary-labor firms is just plain crummy.

51job Price Stock Chart by YCharts

This time around, investors are asking less about when U.S. companies will start adding jobs and more about how. Will corporations still hire executive headhunters to vet and recruit, or will online job posting overrun the traditional practices? Will temping be the new permanent job? And can any company make money in this business with job listings all over Facebook?

YCharts Pro finds that many of the major players here still hold decent balance sheets, and the charts peg several as undervalued. But in a jobless recovery of uncertain duration, they’ll each have their crosses to bear. Here’s a look at a couple outside of traditional executive recruiting.

Robert Half International (RHI) managed to make money straight through the recession, unlike most everyone else in the jobs business. But expectations that its temp placement strengths would make its shares seriously outperform others didn’t really pan out. Corporations haven’t hired a ton of temps in the downturn either.

But earnings at Robert Half have shot up this year, with profit growth coming from all over the world.

Robert Half International Net Income (TTM) Stock Chart by YCharts

The company’s strength now appears to lie in permanent job placements, a higher margin business than temping services. The share price at 1.14 times sales is relatively low for the company’s range but on the upper end of the sector.

With the exception of a few months in late 2010, Monster Worldwide (MWW) has been a pretty consistent dog for investors since the recession began. Even with a 21% price jump one day last week, the shares are down 64% this year alone. (It lost more than half that recent gain over the next three days.)

Monster’s once innovative set-up of making job listings and resume collecting easy online has come back to bite it in an age of social media. Workers and employers troll a whole lot of jobs on Facebook and LinkedIn (LNKD) now.

But Monster finally found friends on Facebook too, and a few other means of boosting its bottom line. Revenues have grown more than 25% in the past 12 months, earnings are back in the black and profit margins are improving.

Monster Worldwide Operating Margin (TTM) Stock Chart by YCharts

The company’s share price at 1.21 times sales still makes Monster look expensive compared to a rash now trading at under 1.

In China, 51job is still reporting massive revenue growth as it moves out of just printing its ads in newspapers to offering services. But the company’s price/sales ratio of nearly nine times anything else in the sector makes it a rather moot discussion for value investors. Even if it did make off with the best ticker of the bunch.