When he worked at Google, Patrick Keane got a lot of calls from recruiters. For a while, as director of sales strategy and field marketing, Keane would get a new offer every week practically begging him to sign on as the CEO of a “weird-undefined-logo tech startup,” as he puts it.

Keane eventually left, joining the ranks of hundreds of ex-Googlers GOOG who have jumped into the eager embrace of a tech world wowed by the fabulous rise of the Mountain View, California-based company. Since it went public in 2004, Google’s DNA — from HR’s impossible brain teasers to the rabid focus on data in its decision-making — has conferred on its engineers a desirability that may be unparalleled in Silicon Valley. What about Google’s sales and marketing people? Results have been mixed.

The best-known Google expat is likely Sheryl Sandberg. Formerly the company’s global online sales and operations VP, Sandberg is now COO of Facebook and a bone fide business superstar. There’s also Suhkinder Singh Cassidy, formerly Google’s top sales executive for Asia-Pacific and Latin America. She founded shopping site Joyus.com after a stint as CEO-in-residence of Accel Partners and CEO of Polyvore. Google’s charismatic Middle Eastern marketing head Wael Ghonim took leave from his job to help catalyze the Egyptian revolution. And Keane, meanwhile, became the CEO of web publishing company Associated Content before selling it to Yahoo YHOO for $100 million last summer.

There are plenty of less-than-stellar performances, though. Tim Armstrong is perhaps the company’s best-known flameout. The former Google sales boss has so far failed to stem the bleeding at the perpetually struggling AOL AOL . He brought in and then canned former Googlers like head of ad sales Jeff Levick and head of media David Eun. The company has sputtered from strategy to strategy after early efforts to apply a Google-like focus on data failed.

Others might have just picked the wrong company. Margo Georgiadis, Google’s former VP of global sales, spent just five months as the COO of Groupon GRPN before returning to the search giant as the head of ad sales and operations in the America’s. In 2008 Southeast Asia sales chief Richard Kimber became the CEO of Friendster – which despite its tarnished reputation stateside — was later sold to Malaysian company MOL global, and is now a gaming site. Elsewhere, some blogs have been less than kind to some former marketing execs, and some startups end poorly.

Given the challenges of working elsewhere — no free food, no climbing wall — why would an employee leave at all? Google is consistently in Fortune’s top 5 best companies to work for ranking, and the company has recently been hiking salaries in an effort to stem brain drain to competitors like Facebook. (The company declined to comment for this story.)

Non-engineers at the company face unique roadblocks, for one. Decision-making is famously numbers-based, and the leadership has traditionally disdained advertising. An intensely quantitative culture can make it difficult for sales staff (or any non-engineer) to get noticed.

And then there’s the draw of the startup. Many simply feel they can make a bigger name for themselves faster by leaving Mountain View. There’s a high demand for sales folk as well as marketing employees. “People that have been with Google for a few years on the marketing side are highly sought after,” says David Voss, COO of Silicon Valley executive staffing firm Foxhunt. “I’d say in the top 1%.”

Says former Googler Keane, “Google’s a good place to poach sales talent. There’s a good farm club.” Ex-Googlers led enterprises tend to command more attention from the media and investors alike. Plus, it’s hard to pass up the chance to be the top dog at a growing company, even one not as iconic as Google. “There’s something very satisfying about having the ultimate authority,” Keane says.

Of course, many ex-Google employees have yet to meet success or failure. There are former Google marketing or sales employees at promising startups including (but not limited to) FriendFeed, Media6Degrees, Factual and Edo Interactive. Other sales staffers left for spots at the likes of LimeWire and web video startup Veoh, which was bought while on the brink of bankruptcy. For now, whether they turn out more like Sheryl Sandberg or Tim Armstrong is anyone’s guess.