The Mac OS X update, dubbed "Panther," highlights the different tacks the rivals have taken when it comes to updating their operating systems.
Microsoft has not released a significant upgrade since Windows XP debuted in October 2001. The company has promised the next major upgrade, now referred to as "Longhorn," will be a significant advance, although the release is not expected until 2006.
In contrast, Apple has had three major updates to Mac OS X since itsin March 2001.
The latest incarnation, version 10.3, goes on sale Friday at 8 p.m. in any given locality, with Apple's retail stores planning special events to attract buyers. The OS carries a retail price of $129, although customers who purchased a new Mac or a copy of Mac OS X after Oct. 7 can buy it for $19.95.
Among thein Panther are an improved Finder, the ability to more easily synchronize files online and the addition of Expose, a feature that makes it easier to find a specific window on a crowded desktop. The OS also enables Macs to better coexist in a Windows-dominated world by allowing the Apple's built-in e-mail and address book programs to get information off a Microsoft Exchange server.
"With 150 improvements it really is like getting a new Mac," said Mac OS X marketing director Ken Bereskin.
Jupiter Research analyst Michael Gartenberg said companies walk a fine line when deciding how to time their releases.
"The key to doing an OS update is you do them when you are ready," he said.
"It looks like Microsoft is really trying to make some fairly dramatic changes (with Longhorn). That's why its taking longer," Gartenberg said. "Apple has already been through the really dramatic change (with Mac OS X). It's easier for them to get releases like Jaguar and Panther out the door."
Microsoft customers are also slower to upgrade, with many not having yet made the transition to Windows XP. Apple customers, on the other hand, have shown a willingness to pay for the frequent updates that Apple has offered, Gartenberg said.
"Their core base has shown historically that they are not averse to paying for features," he said.
The issue, then, is whether Apple has managed to pack enough into Panther to make it worthwhile.
Gartenberg and IDC analyst Roger Kay said Panther will definitely appeal to those who have not yet upgraded to version 10.2, also known as Jaguar, while Kay said it may be a tougher call for those who recently paid to upgrade to Jaguar.
Apple's Bereskin shrugged off concerns that the company might be coming out with paid upgrades too often. "Mac users expect us to innovate every year. For $129, we think it's a great value."
Bereskin noted that Apple has volume license agreements that allow larger customers to pay for a three-year maintenance agreement that includes all Mac OS releases during that time. Costs for businesses range from $207 for those buying 10 to 99 licenses, to as low as $147 for those buying 1,000 or more licenses. The company also has a "family pack" which allows the same copy of OS X to be installed on up to five machines in the same residence.
Separately, Apple on Friday released an update to its iSync program that allows Macs to share calendar, contacts and other information with Palm handhelds, iPods and cell phones. Version 1.3 adds support for a variety of new phones including the Sony Ericsson P900 and T630, as well as the Nokia 3650 and N-Gage phones.
iSync also syncs with the pictures stored in Apple's address book, allowing certain phones to display a caller's photo.