Apple Inc. is known for its revolutionary and innovative products. But that doesn't mean that devices meticulously designed by the top-notch engineers at Apple are free of any issues.

Last year's iPhone 4 had to contend with "antennagate," the controversy about the iPhone's deteriorating phone signals, which were not as strong as they should have been. Users of this year's iPhone 4S -- which has the same design as the previous iPhone, but which now has an upgraded camera and processor, as well as a built-in voice assistant -- are complaining that the battery life is shorter than the advertised 6 hours of 3G browsing or 9 hours of Wi-Fi browsing. Aside from the issues of the battery being supposedly drained by iOS 5 and its location-tracking feature, the new smartphone's major draw, the virtual assistant named Siri, has her own set of problems. Here are a list of the top six problems users have noted regarding the new iPhone 4S:

1. Outages. The iPhone 4S's voice assistant, Siri, has suffered outages or intermittent failures. Although the service is back to normal, Apple didn't say that the "unable to connect to the network" problems won't happen again. What's worse, when the network is down, Siri couldn't even perform basic tasks like voice-to-text. Apple did label the service as a beta, though. PCWorld's David Daw says Apple can't seem to get its cloud services right, noting that Apple's pre-iCloud, MobileMe suite of Web services had long periods of unexplained downtime. But Apple should at least make some public announcements when the service is down.

2. Can't Do Basic Tasks When Down. When Apple's network is down, Siri couldn't even do basic tasks, even those that do not require an Internet connection. Apple should have designed Siri to be able to at least open apps, dial a number or do a search -- even if the cloud services are down. "While it's understandable that Siri would need to contact the Internet to download, say, listings for restaurants in a user's immediate vicinity, it also needs online access to schedule a lunch appointment and play music stored on an iPhone," says the New York Times' Nick Wingfield.

3. Can't Open Apps Even When Up. You can ask Siri to get weather reports, set meetings, send text messages, read e-mails aloud and search through your contacts, among other tasks. But Tony Bradley, writing for PC World, notes that Siri can't open apps like Twitter or Facebook, and it can't take pictures. He says that Apple needs to make available the APIs that would allow third-party developers to tap into and integrate with Siri.

4. Lost in Translation. The iPhone 4S is designed to be a world-phone -- the device has a combined GSM/CDMA antenna, so when you travel abroad with an unlocked $649 iPhone 4S, you can insert a micro SIM from a local network. Siri recognizes English, French and German. And even if you speak English, the virtual assistant won't recognize anything you say if your accent is too thick. Siri only recognizes American, Australian and British English for now. And for other foreign languages, Siri is "No hablo Espanol" and "Wo bu hui shuo zhongwen". Apple CEO Tim Cook is eyeing Apple's expansion in China, where there are one billion mobile subscribers. The iPhone 4S will be available in Hong Kong on Nov. 11 and in China next month. While Siri is the most prominently featured part of the device, CNBC points out that the voice recognition technology doesn't recognize Mandarin or Cantonese. Apple, however, has said that more languages would be added over time.

5. Opens Without a Passcode. By default, Apple allows you to access Siri without unlocking the phone. Unless and until Siri is reprogrammed to recognize only the owner's voice, the security passcode in the iPhone 4S is useless. "The very point of having establishing a passcode lock is to prevent unauthorized access to my iPhone and the information it contains. Allowing Siri to circumvent the passcode and share that information violates the concept," PC Mag's Bradley says. However, Apple has already released iOS 5.0.1 to developers for testing, and this update will hopefully fix the bugs affecting battery life and improve the phone's security features.

6. Not 100% Reliable. "Mark my words: Siri will be as big or bigger than the iPad. It's the beginning of actually useful natural language processing and associated automation," says Jonathan Feldman in Why Apple's Siri Will Change Everything, which appeared in Information Week. But presently, Apple has to have Siri working 24/7. Many cloud or Web services occasionally have blackouts (like the BlackBerry Messenger or the PlayStation Network). Siri, which goes directly to Yelp and other databases (thus bypassing Google), for its answers, should be programmed to visit Google's search engine when Apple's servers or databases are down. Siri is still in beta and its functionality is still limited. For the moment, Siri is not that intelligent either. A user, MattD80, complained in one of Apple's forums that his wife's name is April. When he tells Siri to "Call April," it creates a calendar event titled "Call" on April 1, 2012 instead of placing a call to April, his wife. "Unfortunately, I believe that Siri is more sizzle than steak at this point, and it only delivers on a fraction of its enormous potential," says Intomobile's Marin Perez, in his review of the iPhone 4S.

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