I am an original iPhone user, but I only did so on condition that I could remain on T-Mobile. I unlocked and Jailbroke my first generation iPhone, and loved every bit about it! Now that the new iPhone is out and my T-Mobile contract is approaching its end, I decided to buy the new 3G iPhone and give AT&T a try. At the same time, for the last few days I left my T-Mobile phone running. Here are the results of my findings:

Network

The first thing I noticed when I turned on my 3G iPhone on the AT&T network is that I have only about 1/4 the bars I do on T-Mobile on average. It seemed to vary depending on my location, but overall AT&T, at least in my area, seemed to have a poorer signal.

Here is a picture of my original iPhone on T-Mobile - notice all 5 bars:

Here is a picture of my new 3G iPhone on AT&T - notice only 2 bars!:

However, during some tests I did later, I noticed that when I turn off 3G on my new iPhone, the AT&T iPhone goes back up to 5 bars. It seems that the 3G has some affect on the phone signal - something to remember if you need a stronger cell phone signal. Here’s my new AT&T iPhone with 3G turned off:

Speed

The obvious difference currently between AT&T and T-Mobile is that T-Mobile has not yet converted to the coveted 3G network in the United States. They will be rolling out nationwide in September we’re told, but at the moment, Edge is your only option. So speed is certainly a difference between the two phones. I decided to try an experiment to see if Edge on T-Mobile was as fast as Edge on AT&T. You can see my findings in this video:

As you can see, there really is no difference in Edge performance between the two networks. In the example I showed, AT&T performed a bit faster, but what I didn’t show is that right before this I did the exact same experiment and T-Mobile came up first. It seems despite some latency issues at times, the two networks are essentially just as fast, which would make sense considering it is the same technology.

I also wanted to see the differences in speed between 3G and Edge. So I took the same video like I did in the above example, and ran the video in Edge on the old iPhone at the same time in 3G on the new iPhone. Here you can see the results:

As you can see, 3G truly is almost exactly twice as fast, just as Apple says. So speed truly is a matter of “What you see is what you get.”

Price

Now for pricing. I decided to take my existing family rate plan on T-Mobile, add unlimited data to both mine and my wife’s accounts, along with unlimited text messaging, at 700 minutes per month. Granted T-Mobile does not have rollover minutes, but let’s just try to compare apples to apples.

Taking the exact same 700 minute family time plan on AT&T and comparing it to T-Mobiles and what we are paying currently, based on my last bill, AT&T will end up costing me almost exactly $40 more per month than T-Mobile does currently. The added advantages I get from AT&T from a service perspective are rollover minutes and 3G, so I guess it’s up to the individual to determine if it’s worth it for higher speed and re-usable minutes. For me that 3G is crucial so at the moment that will be the choice for me.

Now, the other little known fact about pricing is that, should you go with a T-Mobile contract, T-Mobile charges you $200 per line to terminate your contract early, and it is not pro-rated. So I get charged the same $200 per line now with only 2 months left as I would have at the beginning of my plan, costing me a total of $400 if I were to terminate now with T-Mobile. So I’ll be left to reducing my T-Mobile plan to the very cheapest plan available and letting it run out. Not a wise plan on T-Mobile’s part if you ask me, since I have to make the choice between them and AT&T.

AT&T’s early termination fee is $175 per line. However, their plan is pro-rated to $5/month. Therefore, if I terminate early now I pay $175 per line, but if I decide 2 months from the end of my plan, I pay next to nothing. Because of that, IMO, AT&T is much less of a rip-off. These early-termination fees alone could make AT&T the actual cheaper choice.

Hassle

Hassle is obviously an important factor between AT&T and T-Mobile for the iPhone. Obviously, unlocking the iPhone 3G for the average Joe is not quite possible yet, and therefore it is absolutely not possible to use it on T-Mobile. However, when it is available, it’s simply a matter of running a simple Mac or Windows program and voila, your iPhone can now run on T-Mobile along with the ability to customize your iPhone beyond what its current capabilities provide. I argue though that having to re-do this every time Apple releases a new software update does add quite a bit of Hassle, and you have to weigh that.

With my AT&T phone, while I do have the hassle of dealing with a closed system and relying completely on Apple for the updates I need, I do not need to worry about re-updating for each software update provided. True, I could also jailbreak my AT&T phone, and in that case the hassle would be the same between the two.

Features

As far as features go, the only difference between T-Mobile and AT&T on the iPhone is that AT&T provides Visual Voicemail, and T-Mobile doesn’t. I really like the Visual Voicemail feature thus far, but I really don’t use it much. I generally forward my calls through Google’s Grandcentral so not many people actually call my direct cell phone number. This makes that feature mostly useless for me.

So in the end, the major difference I’ve discovered between having an iPhone on AT&T vs. T-Mobile is the price. AT&T is quite a bit more expensive on a month-to-month scale, however, if you ever need to cancel your plan, T-Mobile will leave you hanging. Other than that, the two are exactly the same.

Have you run your original iPhone on T-Mobile? Are there any other differences you have noticed?