The iPad may have the highest customer satisfaction ratings of any tablet in the world, but Microsoft cofounder Bill Gates thinks that many of its users are “frustrated” because it doesn’t come with a physical keyboard and it lacks access to Microsoft Office. Business Insider reports that Gates, while being interviewed on CNBC on Monday, said that a lot of iPad users “are frustrated, they can’t type, they can’t create documents, they don’t have Office there.” As an alternative, Gates plugged Microsoft’s own Surface tablet that features the “portability of the tablet but the richness of the PC” and that not coincidentally has a physical keyboard accessory and access to Office. Of course, given how weak the Surface’s early sales have been compared to the iPad, it’s tough to argue that any frustration with Apple’s tablet is prompting consumers to flee to Windows-based tablets.