The iPhone 4 has definitely renewed the interest of people in Apple’s smartphones, and it has already sold over 50 million units worldwide. It is one of the best smartphones, and no other device has come even close to providing the same stylish look, powerful internal specs and ease of use to its users.

The high resolution, 960×640 3.5 inch touch screen is simply marvelous, and the text is very sharp even when a whole Web page is displayed on it – you really have to see it to understand how the resolution affects the way you look at the phone and the display itself.

The specs are also among the best – a 1GHz Apple A4 processor powers it, and with 512 MB of RAM, it is simply the fastest smartphone you can buy right now. Not even the iPad or other tablet PCs like the Galaxy Tab are as fast as this mini-computer. And of course, it can do everything the iPad, and by proxy, a desktop PC can do.

That is why the iPhone 4 is the perfect device for business professionals and people who want to have everything that deals with their time, contacts, schedule, work and electronic data in their pocket. Here are only the most important reasons why the iPhone 4 is the best portable digital assistant (or companion) money can buy.

It’s extremely portable and pretty durable. It goes without saying that it’s portable. It can fit in any pocket and it’s even slimmer than the previous iPhone 3GS. The materials it’s made of are very strong – the metal frame will hold any kind of abuse, and the Gorilla glass on both sides can be bent to incredible angles before it even starts to crack (check out the demo video on Youtube).

You can surf the Web. The Internet is a big part of everyone’s life, and if your work is based online, you must definitely be able to always stay connected, otherwise you’ll simply lose money or social networking contacts. The iPhone 4 can display any kind of Web page, and you can use any online service you need.

You can edit documents. Document editing has been on the iPhone since the first iteration, but never has it been this good. With the fast hardware and high resolution screen, you can edit any kind of documents you want, from .doc files to Powerpoint presentations (which you can also output to a projector!). The Autocorrect feature has also gone a long way and you can now trust it to complete and correct any words you need very quickly.

You can use it for sensitive information. There are dozens of highly encrypted storage apps for sensitive data like passwords, credit card info, personal information and other data. You can be sure that no information you store on your iPhone 4 will ever get stolen or lost, especially if you use an online backup service like Dropbox (and store the encrypted data, of course).

You can use it as a universal communicator. You can make calls and send messages to any platform you want. Aside from the usual cell phone and landline calls, you can use it to talk with users from Skype, MSN, Yahoo messenger, Google Talk, Facebook and most other online and VoIP services. You can also place live video calls and stream video right to your viewers on the Web using the front and back-facing cameras.

The iPhone 4 is an excellent Personal Digital Assistant for anyone who values their time and wants to better manage it. It can accomplish any task you can throw at it with ease, it looks amazing and it’s very portable for such high specced internal hardware. Apple has really created one of the best smartphones that actually transcends into the universal computer realm, because even with such a small screen it has a high enough resolution to display any kind of data.