Apple Inc. last summer brought out a promising new service called MobileMe designed to synchronize email, contacts and calendars among any combination of its own Macintosh computers and rival Windows PCs, plus Apple’s iPhones and iPod Touch devices. It also offered online email, contacts and calendar, online photo galleries, syncing of Web bookmarks and 20 gigabytes of online storage.

The main idea was to replicate for consumers the kind of seamless, over-the-air email, plus contact and calendar updating, available to corporate users via systems like Microsoft’s (MSFT) Exchange.

The only problem was that MobileMe, which costs $99 a year after a 60-day free trial, and is available at MobileMe.com, was so buggy and ragged that I couldn’t recommend it. Apple (AAPL) pledged it would fix MobileMe. So, I have just spent a few weeks testing it again on multiple Windows and Mac computers, and an iPhone.

This time, my verdict is different. Apple has fixed all of the speed and reliability issues I encountered last year. In my new tests, MobileMe’s email was prompt and reliable. I was able to add, delete or edit a contact or calendar entry on one device, and see these changes almost immediately on all the others, and on the MobileMe Web site. The Web-based photo gallery, which can also house videos, worked fine on both Windows and Mac, and I was able to upload photos to it from my iPhone. The file storage also worked well, and now has a feature that allows you to share files too large to email. And each MobileMe account works with an unlimited number of computers, iPhones and Touches.

But there is one major caveat. While MobileMe works with Windows, it works better with Macs. The main reason for this is that, as I noted last year, its synced calendars and contacts show up in an odd manner in Microsoft Outlook, the most popular calendar and contact program in Windows.

Apple acknowledges the Outlook problems, which show up only in a mixed environment of Macs and Windows PCs, and pledges they will be fixed by the fall. The company says that if you are using MobileMe solely on Windows PCs, with or without an iPhone, the Outlook problem shouldn’t appear in most cases.



Apple’s MobileMe Apple’s MobileMe

There are other drawbacks for Windows users. While the Web version of MobileMe works fine on Windows in the Firefox Web browser, or with the Windows version of Apple’s Safari browser, Apple warns that it might not work properly in Microsoft’s Internet Explorer 7. The site worked well in the new Internet Explorer 8.

In both versions of IE, my tests showed that another MobileMe feature, bookmark syncing, didn’t work as advertised. Some bookmarks didn’t appear at all; others were listed alphabetically instead of in their original order. Apple is promising to fix this problem as well.

Some features are available only on Macs. For example, you can upload photos and videos to your MobileMe galleries directly from Apple’s iPhoto and iMovie programs. On Windows, you have to upload these using the MobileMe Web site.

The Outlook problem works this way. If you have a mixed group of Macs and PCs, and your Mac’s calendar isn’t named Calendar, its information won’t sync with the main calendar in Outlook. It will appear as a separate calendar that requires extra steps to make visible. Worse, if your Mac or iPhone address book contains subgroups of contacts, these appear as separate address books, which require extra steps to make visible and may not properly sync up the same names as the Mac contact groups.

However, MobileMe now finally does a fast, reliable job of syncing calendar and contact items. In my tests, I was repeatedly successful in doing this in a variety of scenarios. I added a new phone number to a contact on my iPhone and, a minute or two later, it was added to that contact in Outlook, in the Mac’s Address Book program and in the Web-based MobileMe address book. I then changed the contact again in Outlook, and again in the Web-based address book, and the changes appeared everywhere else.

The same process worked with calendar items. None of this required cables (though, for Windows computers, you must first download and install a MobileMe control panel that runs in the background). The only glitch I ran into, which Apple is promising to fix, is that when I switched my iPhone to sync with MobileMe, it wiped out all the custom ringtones I had assigned to particular contacts.

Apple’s $99 price may seem high, given that you can get some features for much less, even free. And MobileMe lacks some obvious features, like online backup or automatic syncing of all files. Also, there’s no way to create limited access to allow an assistant or family member to use just your MobileMe online calendar.

But MobileMe finally does give consumers the main email, contact and calendar convenience corporate users rely upon daily.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.