Should I upgrade to the iPhone 4S for Siri?

Apple's voice-activated, personal assistant, Siri, is a cool app to show off at parties, but is it useful enough for me to upgrade to the iPhone 4S? And how can I make sure that I don't get socked with a surprise $1,000 bill when I return from my winter vacation in the Caribbean Islands?

These are the questions Ask Maggie tackles in this edition.

Should I upgrade to the iPhone 4S for Siri?

Dear Jim,

I have mixed thoughts about the Siri application. It's definitely cool to speak into your device, ask a question, and have Siri answer you. And some people I've talked to who own an iPhone 4S really love it. But the times I've tried the app, it hasn't worked that well for me. It doesn't understand what I am saying, or it just directs me to a Website without telling me the answer I wanted. So in my opinion, the app can be useful at times, but it's more a novelty at this point than a reason to buy the iPhone 4S.

Even though I don't think Siri is cool enough to make me upgrade to the iPhone 4S, there are many other features of the iPhone 4S that are worth upgrading for. And without a doubt, the iPhone 4S is a big improvement over the iPhone 3G, which is now two-generations old.

The biggest benefit for you is that the the iPhone 4S will likely offer you those faster downloads you want. The iPhone 4S sold by AT&T operates on the carrier's HSPA+ wireless network, which is a slightly faster network than AT&T's regular HSPA 3G network, which the iPhone 3G uses.

But just to be clear, the iPhone 4S does not operate over AT&T's new 4G LTE network, which promises to offer much faster download speeds. (There has been a lot of talk about 4G LTE networks and I just wanted to be clear that the "4" in the name of the iPhone doesn't mean it supports this network.) Most Apple iPhone fans are hopeful that 4G LTE will be coming to the next iPhone that's released. But it's unclear when that new phone will be released.

In terms of device performance, the network is just one piece of the puzzle. The real difference in download speed between the iPhone 3G and the iPhone 4S is likely attributable to the fact that iPhone 4S offers more processing power than the older iPhone 3G. So everything you do with the phone should be noticeably faster--from downloading e-mail to surfing the Web to switching between applications. The overall response time of the iPhone 4S will just be snappier than what you're used to.

There are also many other improvements on the iPhone 4S over the iPhone 3G. For example, the iPhone 4S offers a better camera with a built-in flash. It also has a front-facing camera, so you can use the FaceTime video chat app. The iPhone 3G doesn't have a front-facing camera and can't support FaceTime.

The screen on the iPhone 4S is much clearer than the one on the iPhone 3G. Also, you are not able to run Apple's latest iOS 5 software on the iPhone 3G. This software upgrade gets you access to a whole slew of new features, such as Apple's cloud-based music and storage services. And it also gives you access to iMessage, a nifty messaging application that allows you to text message other iPhone users without using up carrier text messages. iMessage bypasses the carrier SMS system so you can text for free with other Apple iPhone users.

So in short, the iPhone 4S is a solid phone that gives you much more than what you're used to with the iPhone 3G.

Now, you could also consider something other than an iPhone for your next smartphone. There are plenty of Google Android devices to choose from on AT&T as well as other carriers. And many of them will offer similar features to what you can expect on the iPhone 4S. AT&T is also now offering some Google Android devices with 4G LTE capability. These smartphones should offer you fast e-mail downloads and Web surfing when you're in 4G territory. But AT&T has only deployed 4G in limited areas, so you may not be able to access that network even if you have one of these phones.

If you're willing to wait a couple of months, you can also consider a Microsoft Windows Phone. I checked out the new HTC Windows Phone smartphone and Nokia's Lumia 900 at CES. And I really liked these phones. Windows Phone is an intuitive and easy to use platform, so I think it's worth considering. And both the HTC Titan II and the Nokia Lumia 900 are good smartphones, with advanced cameras and other hardware goodies that rival the iPhone 4S.

But since you already have an iPhone 3G, and it seems like you like the platform, I'd suggest just sticking with Apple. All your contacts, music, and most importantly all your apps will load easily onto the iPhone 4S. If you switch to the Google Android or Windows Phone platforms you will have to re-download and even repurchase your apps. Most of the apps you had on your iPhone, will likely be available on Android, but you may not have the same luck with a Windows Phone device.

Even though Microsoft is quickly adding more apps to its marketplace, the company still doesn't have the same exact catalog as Apple or Android. For example, Words with Friends, the popular online Scrabble-like game that everyone is playing these days, isn't yet available on Windows Phone. It will probably be on Windows Phone at some point, but it's not there now.

So to summarize: if you are in the market for a new smartphone right now, I think someone like you, who is already a happy Apple iPhone user, can't go wrong with the iPhone 4S. Also you will have a lot of fun with Siri, but just don't expect too much of her just yet.

Take care. And good luck!

Avoiding 'bill shock'

Dear James,
The first thing you need to understand is that your U.S. voice minutes and unlimited data plans don't apply when you're traveling internationally. So the phone calls you make and receive and the data you use while on your trip will not be counted toward your monthly total for your regular AT&T plan. Instead, you will be charged per minute when it comes to voice and per kilobyte or per megabyte for data.

As you have probably heard, those roaming charges can be hefty. And people have been known to rack up massive bills while talking, texting and surfing the Net on their wireless devices while abroad. To make sure you are keeping your costs in check, you should sign up for an AT&T international plan before you leave home. You can access information about AT&T's international plans on the Web. Check to see if the countries you are traveling to are included in AT&T's international plan. And then you'll just sign up for the plan right before you leave for the trip.

The way these plans work is that for voice services, you will still pay per minute, but with the international plan, the per minute rate will be reduced. For data, you will sign up for a certain package for a flat rate. For example, you could get 50MB of data for $25. And each additional 10MB you use, you'd be charged another $10. AT&T's international plans go as high as $100 for 800MB of data.

Remember that you will just be signing up for the international service just before your trip, since you don't need it until you are abroad. If you want to use the full 25MB or even the full 800MB of data that you're paying for as part of this plan, make sure you wait until your billing cycle ends before you cancel the service.

If you cancel the service in the middle of your billing cycle, AT&T will prorate the cost of the service as well as prorate the amount of data you can use. So you could end up spending more if you exceed the monthly data cap on the International plan.

Your iPhones and iPads will allow you to track usage while you're away, so try to keep track of how much data you are using so you don't go over your limit. Since it's very easy to exceed these caps and those charges can add up quickly, I would use data service while you're on vacation much more judiciously than you do at home. If the cruise ship you are on has Wi-Fi or there is Wi-Fi in the cafes when you're in port, I'd use those networks as much as possible. Remember that when you use Wi-Fi, you are not using any carrier data. So all that usage isn't counted toward your monthly total.

I hope that information helps save you from bill shock. And I hope you and your wife have a fantastic vacation!

Ask Maggie is an advice column that answers readers' wireless and broadband questions. The column now appears twice a week on CNET offering readers a double dosage of Ask Maggie's advice. If you have a question, I'd love to hear from you. Please send me an e-mail at maggie dot reardon at cbs dot com. And please put "Ask Maggie" in the subject header. You can also follow me on Facebook on my Ask Maggie page.