Apple's release of iWork '08 is "embarrassing," an analyst said Friday, not for its maker, but for Apple's rival, Microsoft.

On Tuesday, Apple rolled out a refreshed iWork that added a spreadsheet, dubbed Numbers, to the earlier mix of a word processor/page layout Pages and presentation maker Keynote. But it was iWork's ability to handle the Open XML file format - the new native format for Microsoft's own Office 2007 application suite - that Michael Gartenberg of JupiterResearch talked about.

"This was the ultimate insult to injury," Gartenberg said. "Not only has Microsoft not delivered the ability to read and write Open XML in its Mac Office, but at the end of the day, Apple was the one who delivered."

Gartenberg referred to Microsoft's problems developing Office 2008 for Mac, which the company recently announced would be delayed until mid-January. Among the roadblocks, said Microsoft's Macintosh Business Unit (MBU), is the shift to Open XML as Office 2008's native file format. The company has also been slow in releasing conversion tools that let earlier editions of its Mac suite work with Office 2007's Open XML documents.

"This is embarrassing for MBU," Gartenberg said. "It has said that the shift to Intel has caused its problems, and changes in development tools, and the file format, too. But every other major vendor has pretty much managed to get their apps over to Intel on the Mac. Microsoft is one of the oldest Mac developers out there, so it's not like it doesn't have experience on the platform."

IWork '08 applications can open the OpenXML formats churned out by their Office 2007 counterparts - Pages with Word, Numbers with Excel, Keynote with PowerPoint - but cannot save in those formats. Currently, Office 2004 and Office v. X users can both open Word and PowerPoint Open XML files and save in those formats using beta converters MBU has issued. No such converter has been released that handles Excel 2007's Open XML files, however.

Ironically, one of those who praised iWork's handling of the Microsoft file format was a program manager for Office 2007. "iWork '08 reads the Office Open XML files with very high fidelity," said Brian Jones on his company blog.

At the same time, Jones defended his fellow developers at Microsoft in MBU. "The Mac Office folks have a ton of stuff they are working on for the next version, so it's not surprising that you aren't seeing full Open XML support until they reach that point," Jones said in response to a question asking how Microsoft lost the race to Apple's iWork.

"Office for the Mac is just not a real priority for Microsoft," said Gartenberg as he spelled out his take for Microsoft's tardiness creating software on the Mac that can handle what are, after all, its own file formats. "And that's not likely to change anytime soon."

Asked to explain why Microsoft hasn't been able to match Apple, MBU's marketing manager, Amanda Lefebvre, ticked off the development issues that have delayed Office 2008.

"The transition to the new file format is one of several reasons the development cycle is longer with Office 2008," she said. "Office 2008 [for Mac] will run natively on Intel- and PowerPC-based Macs with a Universal Binary [and] this transition necessitated a switch to a new set of development tools as well. The combination of these two technology shifts definitely impacted our schedule."

Not quite, Gartenberg said. "What this really shows is Microsoft's inability to ship software on time these days," he said.

Apple, meanwhile, is doing the smart thing. "They're making sure that they're not dependent on Microsoft for any of the important software for the Mac," said Gartenberg.

That strategy, along with the £55 price of iWork and the window of opportunity because of Office 2008's delay, puts Cupertino in the cat bird seat. "It's going to be hard for Microsoft to get those people who try and buy iWork back," he said. "Microsoft's let down its Mac customers."