Blackberry
Blackberry is still huge in the business sector. Also sleek and sexy, blackberries are very popular among almost any age group. If you want a physical keyboard for texting, typing emails, etc, a blackberry is likely for you. Iphones don't have a physical keyboard and most of the android phone's don't either. Some android phones do have physical keyboards but I still think blackberry's physical keyboard is its greatest asset. However, the OS on the phone isn't as great as the other two especially since its not as easy to install you're own custom applications and such like a jailbroken iphone or open source android. Furthermore, web surfing is severely reduced since it lacks a touch screen (not including the storm, which isnt that great anyway). It is much slower to navigate and browse the web. However, if browsing the web is not important, and texting and typing is, blackberries may be for you.
I recommend blackberries to professionals too busy to really need all the other uses a smartphone can do and don't want to get involved in installing custom software and roms. As well, people that need a physical keyboard will love a blackberry.
Iphone
Sleek designs and impressive interfaces with many features, an iphone is a popular choice for many. The OS is good, however, it is very closed off by Apple to make sure they make all the money. The biggest bonus of the iphone is probably the apps and the ability to do nearly anything on it. It's touch screen is amazing and Im sure the Iphone 4 will amaze most. However, if you want a physical keyboard, then the iphone is not for you. The on screen keyboard is good though, and having one personally, I know I can type just as fast as most physical keyboard users. The interface is very very simple, but to truly use your iphone you NEED to jailbreak it. A jailbroken iphone makes a regular iphone pretty worthless. I wont get into much detail on jailbreaking as you can easily look it up on google. If you're willing to jailbreak (which is phenomenally easy), love touch screens and love to surf the net, watch videos and listen to music, the iphone is likely for you. Also, because they are so popular, its really easy to get feedback and help on how to do things as well as solve problems. Furthermore, apple's warranty and replacement policy is amazing. You can literally walk into apple, and get your iphone replaced right on the spot.
Android
Android is an operating system that runs on many new smartphones. Some have physical keyboards and touch screens and some just have touchscreens. It is open source so you can easily install custom roms and many free apps that can make your smartphone device you're most valuable piece of technology. It's kind of in between the blackberry and iphone. Many new phones are coming out with android and I have heard nothing but good reviews. These include many of the new snapdragon processor smartphones (1 GHz speed) and will likely continue to grow. I personally have never really used an android phone but I would love to get one. They are just as sleek and sexy as both the iphone or blackberry. It might however take a little more skill to open up the android device versus the iphone as they still aren't as popular, but if you're willing to google a bit more, you can pretty much do anything you want with your android device that an iphone or blackberry can do.
I recommend android phones to users that want to maximize smartphone usability and aren't afraid to install custom roms and such. Also, if you need a physical keyboard, many android phones can provide this for you as well. Surfing on the web is phenomenal as well due to the touch screen interfaces.
Personally, I have an Iphone 3GS and I will likely upgrade to Iphone 4. However, I'd love to try out android phones but the best ones aren't yet on my provider rogers. But I do love all smartphones!!
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