One month has already passed since the availability of iPad in the US market. But as for 3G model, it was launched only last Friday. According to recent reports Apple soled over one million iPads. If you still do not have the iPad, here is a few things to consider before choosing between 3G or Wi-Fi models.
Cost
Actually, the 3G costs $130 more compared to Wi-Fi. It is explained by the fact, that you have a privilege, i.e. you can use 3G. Also take into consideration that you will have to spend more money for the 3G network.

Apple concluded a good deal with AT&T, according to which in order to use 3G, users will have to pay $15 a month for 250Mb. But if they pay $30 they will get unlimited data access. Moreover, there is no contractual obligation.
Convenience
If you are going to use you tablet device at home, you can take advantage of a Wi-Fi network. It means that there is no use for you to have 3G capabilities.

If you are a business professional, it may happen that you are not always near a Wi-Fi network. So in this case it is better to have a 3G connectivity. It will become your lifesaver. Due to it you will be able to get an urgent e-mail.
Alternatives
Still you are provided with alternatives. If you have a jailbroken iPhone, you can make use of the My Wi app. With the help of it you can connect to iPhone by means of Wi-Fion, the 3G connection of the device. Just the same can be done with the help of a 3G-enabled Windows 7 notebook.

Another solution is to opt for a device such as the Novatel MiFi that is available with connection plans from Verzon or Sprint.

In fact, all these three options offer you a distinct advantage over the 3G iPad, i.e. multiple devices are able to share a Wi-Fi connection. But there is also a disadvantage, you will have to carry with you an additional device.