Apple is one of the major players in Google’s sights, but it’s also a valuable partner, said Google Chairman Eric Schmidt at the All Things D conference Tuesday night.

Schmidt both praised and criticized Apple in the talks, revealing Google and Apple’s complex relationship. Essentially, the companies are partners and competitors with vastly different ideas, Schmidt said. He would know — Schmidt served on Apple’s board from 2006 to 2009 before stepping down as competition between the companies began to heat up.

On one hand, Apple and Google are important partners, having just renewed a contract to have the search company’s Maps application and search come standard on iOS devices.

On the other hand, Schmidt denied the accusations of Apple CEO Steve Jobs, who said having an Android phone is like having a “probe in your pocket.” Schmidt said that Google does not take location information and put it into search.

“The Apple model is the inverse of the Google model.” Schmidt said. Where Apple takes its app curation very seriously, Google leaves the market to decide which products should succeed.

He does have respect for Apple, however. In listing the “gang of four” companies that will shape the Internet, Schmidt named Apple, Facebook, Amazon and, of course, Google. Schmidt also mentioned Twitter and PayPal — which is currently suing Google over its Wallet service — as other contenders, but had no mention for Microsoft.

He also said that anyone looking to improve their security should consider getting Mac over a PC.

Schmidt dropped a couple more interesting tidbits at the talk, particularly about how he views his time at Google. He said he blames himself for Google’s social failures. According to Schmidt, he wanted to partner with Facebook, but they just couldn’t land a deal. He said Google fell down on creating the best way to establish a user’s online identity

“I clearly knew that I had to do something, and I failed to do it,” he said during the talk. “A CEO should take responsibility. I screwed up.”

As for Google’s latest venture into social, the “+1” button, Schmidt said that the button will help Google improve its products, but is not meant to go directly after Facebook.

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