Still considering whether (or indeed how) to purchase the latest iPhone 5 that was released in many parts of the world, though not Chinese mainland, last month? While mulling over that one, Apple fans also need to decide whether to upgrade their existing iPhone and iPad to Apple's latest mobile operating system, iOS 6, which was also released last month.

The mixed reception iOS 6 has received -- rare for an Apple product - makes the question of whether to upgrade a tricky one.

Apple has added 200 new features to the new system, including a Chinese language version of Siri, Apple's voice-activated personal assistant app, and the Panorama camera app. However, the new Maps app is arguably inferior to the previous Google Maps.

Other features include 3D maps (not available on the Chinese mainland) and Facebook, Twitter and Sina Weibo integration.

The iOS 6 also has "China features" that integrate China-oriented functions. These include Baidu's search service, Sina's Weibo (microblog) service, and Youkutudou's video services. Its online video played hours are now 22 percent higher than YouTube's.

Combined, these additions makes the iOS 6 one of the most significant mobile system upgrades in Apple's history since the debut of the first iPhone.

One of the most striking changes to the iOS landscape is the new Maps application replacing Google Maps. This is widely regarded as Apple's final move to distance itself from Google - co-developer of the rival Android operating system - in the fiercely competitive smartphone market.

But getting used to the new Maps app has proved frustrating for some users who have grown accustomed to Google Maps. And iOS 6 users on Chinese mainland must also make do without foreign maps. AutoNavi, a Beijing-based map service firm, provides the Chinese mainland map service on the new iOS for the domestic market, and this service doesn't support overseas maps.

As a result, a search for "New York" will return the Bank of New York (Shanghai Branch) in Pudong New Area but not the Big Apple itself.

Reports of Wi-Fi disruption also damaged confidence in iOS 6. Some users found they lost their Wi-Fi connection for a while after upgrading iOS 6. Apple has since fixed these glitches, but many consumers remain wary.

"It's more like a beta system than a product from Apple," said Jack Gao, a local lawyer with an iPhone 4S. "I'm going to wait until every problem is fixed."

Shanghai Daily tested iOS 6 on a number of devices, including the iPhone 4, iPhone 4S and the new iPad.

For those lucky owners of an iPhone 5 -- while it's been released in Hong Kong, there is no release date on Chinese mainland yet - they are advised to stick with the built-in iOS 6. It's complicated and risky to turn the system back to iOS 5, through jail-breaking or hacker methods.

For other Apple users, here's a rundown of the good and not so good features of iOS 6 to help them decide whether to upgrade.

Siri: A major appeal of iOS 6 for Chinese users is that they can now chat to voice-controlled virtual personal assistant Siri in their mother tongue. Chinese language support has been extended to the third-generation iPad and fifth-generation iPod Touch, as well as the iPhone 5 and iPhone 4S.

During the test, Siri was found to be faster, more responsive and with more personality than before. It can now directly display sports scores and provide movie listing information, including show times, reviews and trailers. But it doesn't support making restaurant reservations nor voice-controlled navigation in Mandarin.

Siri in Mandarin is not available to users of iPhone 4 and iPad 2.

Good stuff: Supports new iPad, easy to check sports results.

Bad stuff: Unable to search restaurant nor offer voice-controlled navigation in Mandarin.

Maps: The completely overhauled Maps app replacing Google Maps is the most controversial update. After all, Google has been developing its map services for seven years, while Apple is just a beginner in this field.

Apple's version of Google Maps was never as comprehensive as the one available to phones with Google's Android system which offers mapping services, Street View and directions, including public transport information.

The new Maps app in iOS 6 builds on voice-guided navigation, for the first time available for iPhone 4S and iPad, making it comparable to Google Maps with navigation on Android phones and Nokia Drive app on the Windows Phone system.

In the overseas market, Maps features new 3D flyover views for major metropolitan areas.

But in the Chinese mainland, however, Maps uses AutoNavi's service, which doesn't feature 3D display.

The latest news is that AutoNavi has advised users to download a map data file, supporting both Mandarin and English, to improve the Maps experience.

Good Stuff: 3D map, voice navigation with Siri support, though not in Mandarin.

Bad Stuff: Time and effort for users to learn the new Maps service and no overseas or 3D maps.

Camera and social integration: The biggest camera upgrade in iOS 6 is Panorama, not from a third-party software developer but Apple itself.

Users can start it simply sweeping the iPhone horizontally to gather a shot and iOS stitches an image. Compared with third-party top panoramic apps like Panoramatic or the Microsoft-developed Photosynth, Apple's own software is quick, reliable and easy to use. The one thing it lacks is an automatic exposure adjustment, which affects the panorama effect in dark scenes.

Other developments see Facebook, Twitter and China's top social media Sina Weibo are integrated into the new iOS 6. Once you set them up, you can share directly to them from any "share" icon located throughout the system, including pictures.

It had previously taken at least one minute to post a picture on Sina Weibo, through opening the application and inserting the pictures. Now the only thing you need to do in iOS 6 is to share the picture directly through new "share" button. In the Shanghai Daily test this took less than 10 seconds.

Good Stuff: Quick and reliable Panorama method, integration of Sina Weibo.

Bad Stuff: Only supports vertical panoramas.

Conclusion: Longtime fans of iOS, you may be slightly disappointed that iOS 6 isn't a revolutionary update, especially for the Chinese mainland. However, it is worth upgrading for majority of users.

If you are happy with Google Maps and not a heavy user of social media, perhaps you ought to bide your time and wait for further updates.

But for most users of iPhone 4S and iPad 2, there's very little reason not to hit the upgrade button.

The new features you gain on balance outweigh the loss of Google Maps. And who could resist the chance to chat with Siri in Chinese?