First thing, I don't have a data plan yet. I don't need it to be honest. But I'm willing to get one by 2nd quarter this year. I'll be running some business that require me to be connected all day. Truth is, why would you get an iPhone 4 if you already have a 3Gs iPhone which runs pretty good compared to other cellphones?
Those just like me, who have no data plan with their carriers, might just consider that getting any iPhone is good since you don't have data access. But I'd like to focus on other non-essential data consumption related issues.
The official Apple chart below, provides a detailed comparison of what's better between the devices in question. (Click on the image).
Besides the obvious matter, what's really into an iPhone 4 that you won't get in a 3Gs? By today's date, you should be more than aware of its existence, and also have heard rumors about an upcoming iPhone 5. When the iPhone 4 was released, the first known issue was with its antenna. The phone itself drops calls if you move it while during a call.
Apple solved this by giving away free plastic cases that prevented the antenna issue. But the truth is, that the phone still fails by design. But let's focus a bit on the real iPhone cost.
An iPhone 3Gs brand new can be found on eBay without a contract for an estimate of $500.00 US Dlls.
An iPhone 4 brand new can be found on eBay without a contract for an estimate of $700.00 US Dlls.
You can also try your luck through the auctions items, and get a 3Gs for as low as $300 US Dlls, or an iPhone 4 around $550. However, we must see if it's really worth spending two more hundred on a new iPhone 4.
If you're gonna get an iPhone 4 through a contract, getting a nice data plan, I would say go for it. But if you're gonna spend on a contract-free phone, go for the iPhone 3Gs. However, if you already have a 3Gs iPhone in any condition, wait for the upcoming release of the iPhone 5, coming up by late 2011, or early 2012.