I would like to review it a bit, because nowadays more and more people like to use them.
Not only because its function, which is very useful, but also because of its prestige.
People tend to look at us from what we wear, what we used and how we speak. And a new hi-tech cellphone is one of it.

Blackberry Bold 2 9700 officialy announced in their stores for T-Mobile on November 11, 2009.
The Blackberry Bold 2 9700 is the latest blackberry to hit the market. Highly coveted, the Blackberry Bold 2 9700 is an excellent option for those that want a high end blackberry. The Blackberry Bold 2 9700 will be fairly similar to the first Blackberry Bold, but with some key differences.
Two of major differences are noticed externally. The first difference between the Blackberry Bold and the Blackberry Bold 2 9700 can be found in the screen resolution. The Blackberry Bold 2 9700 will have a higher screen resolution, making for an optimal browsing and multimedia experience. What may come as a sigh of relief for blackberry users is the change from a trackball to an optical trackpad on the Blackberry Bold 2 9700. Internally, the Blackberry Bold 2 9700 will have Wi-Fi, which has been a highly demanded option.
One of the best improvements that has been said to have been made is the overall improvement in the battery life on the Blackberry Bold 2 9700. If you’ve never used a Blackberry, the sheer power of the Blackberry Bold 2 9700 should definitely make it a must have mobile device. The fact is that blackberries have risen immensely in popularity, and offer a plethora of features to make your life easier. The Blackberry Bold 2 9700 is a feature-laden device that is worth every dollar.

While iPhone 3GS is thought as one of the best smart phone by Gizmodo, there are some improvements than its predecessor,iPhone 3G, such as processor, camera, GPS, compass and many more features.
Front and center is the iPhone’s signature feature: a bright, beautiful high-resolution 3.5-inch diagonal touchscreen, offering a resolution of 480-by-320 pixels. The iPhone 3GS has Apple’s usual complement of four physical buttons (Home just below the touchscreen, sleep/wake up top, a volume up/down rocker on the left side, and a ringer toggle just above the volume controls) and the same black or white plastic back shell introduced with the iPhone 3G.
If you need to know which model is which, there’s only one clear way to do so: Look at the lettering on the back of the phone. If it’s in the same silver ink as the Apple logo, it’s an iPhone 3GS. (Likewise, if 32GB appears below the word iPhone, you know it’s an iPhone 3GS—the previous model was only available in 8 GB and 16 GB editions, while this phone’s capacities have doubled to an impressive 16 GB and 32 GB, allowing users to load their phones up with even more apps, tunes, and videos.)
The best part of this smart phone is the touch screen, I’ve never really found fingerprints to be a major problem with the iPhone, since the device’s screen has always been quite bright.

Now which one will you choose?
For me personally, I will choose Apple iPhone 3GS 32 GB, I've used it already though.
The reason is because features in iPhone 3GS are the most supporting for the work I do.
And you can update or download all softwares you need in an instant. The touch screen gives so smooth responses so I can surf quite freely.

But nevertheless, both are great smart phones, either Blackberry Bold 2 9700 or Apple iPhone 3GS got their own features and function. So it is up to you to choose it based on what you need.