Social Capital CEO Chamath Palihapitiya said Amazon CEO Jeff Bezos is a "fantastic" capital allocator and a maniacal CEO solely interested in running his company.
And Palihapitiya said the exact opposite is true of Apple CEO Tim Cook. Under Cook, Apple has left hundreds of billions of dollars "rotting" on its balance sheet for years, he asserted.
"They have a CEO that is unfortunately, you know, pretty lackluster. I saw him on 'Mad Money' and ... it was like human Ambien. I mean, it was pretty boring," he told CNBC's "Squawk Box."
"As a person that's worked for great leaders, and is around a lot of great technology leaders, it would be very difficult for me to work for him," said Palihapitiya, a Silicon Valley-based venture capitalist and former Facebook executive.
Social Capital has $1.2 billion in assets under management and focuses on early stage investments in education, health care, financial services, and enterprise and consumer segments.
Palihapitiya said he would work for Bezos in a heartbeat, and would have also worked for the late Steve Jobs.
Apple did not immediately return a request for comment.
Palihapitiya made waves at the Sohn Investment Conference this week by forecasting Amazon's value would grow to $3 trillion in 10 years. On Thursday, he had a message for people who question the e-commerce giant's cloud computing business.
"I think that's, to be blunt, a lot of nontechnical people who don't really understand what AWS is," the Social Capital CEO said, referring to Amazon Web Service.
Critics of AWS have said its profit margins could become too thin as the cloud segment becomes commoditized.
But Palihapitiya said these naysayers are missing two simple facts. First, in the 10 years since Amazon launched AWS, it has cut prices roughly once every two months. Second, the company has consistently launched new features to attract customers.
He noted that Amazon introduced 700 features to AWS last year, marking a 40 percent increase over the prior year.
"When you're doing those two things at same time, what's happening is you're disrupting existing incumbents who have no ability to actually offer the same capability at the same price," he said.
Alphabet's Google Cloud is perhaps Amazon's closest competitor, but its focus on offering machine learning capabilities in its cloud computing is a small and specific application for a minor subset of companies, Palihapitiya said.
He said Microsoft's Azure cloud offering is also interesting, but only to the extent that companies care about the legacy Microsoft product stack. That is true of fewer firms today, he added.
In the end, AWS offers a one-stop shop for that nobody else offers, according to Palihapitiya.
Disclosure: Palihapitiya does not personally own shares of Amazon, but he is invested in the company through public investment at Social Capital.
Correction: This story has been corrected to show that Palihapitiya said Amazon's value would grow to $3 trillion in 10 years.