A few Apple fans with loads of free time on their hands are already camping outside the Fifth Avenue Apple Store in Manhattan in anticipation of the next iPhone, which is expected to be formally revealed on Tuesday, September 10, at the company's California headquarters.

But who needs an official launch? Thanks to months of leaked spec sheets and purported photos, we already have a pretty clear picture of what the iPhone 5S will be like.

So, should you buy the next iPhone? Take my hand. Let's figure this out:

What's new with the iPhone 5S?
Not much! In terms of "newness," the next iPhone will look an awful lot like the iPhone 5, with a few iterative improvements:

  • A fingerprint sensor. The iPhone 5S is rumored to have a silver ring around the home button that will serve as a fingerprint reader, which will ostensibly allow users to unlock their phone without having to jam in a four-digit security code. (Photo at the bottom.) Expect Apple to hammer this point home as the iPhone 5S's key differentiator from the iPhone 5.
  • New colors. Expect a few additional color schemes to the traditional black or white options. Gold and graphite are said to be in the works.
  • A slightly better camera. Expect the 5S to retain the 8 megapixel camera of the iPhone 5, with a slightly larger aperture for low-light shooting. (f/2.0 versus f/2.4.) It will also have a brighter dual-flash setup.
  • A better battery, which Apple will probably find a bit of room for.
  • OS 7. I've been testing the beta version for a few months. It's very pretty. But aside from a much better Safari, more intuitive camera software, and smoother switching between apps, it's not a huge jump from previous versions of iOS.

Other than that? The phone should retain the same aluminum chassis, 4-inch Retina display, and general feel of the iPhone 5S. Unless Tim Cook pulls a rabbit out of his invisible hat and surprises everyone....

What kind of surprises might there be?
It's kind of a long shot, but Forbes suggests the screen could be improved "in some fundamental way, perhaps its ability to handle sunlight." Apple has partnered on its displays with Sharp, which has used glare-reducing technology on its TVs. The real surprise might lie in Apple's pricing structure, however, namely for what's probably going to be the plastic-bodied iPhone 5C.

What is the iPhone 5C again?
Imagine the shape and capabilities of the iPhone 5, including the 4-inch display, but instead of a brushed aluminum body, the back will come housed in plastic. Unlike the high-end 5S, the iPhone 5C is rumored to be coming in a wide variety of bright colors, kind of like the iPod.

Why would anyone want a plastic iPhone?
It's a lot more affordable, from both a production and retail standpoint. The iPhone 5C is mostly for markets outside of the United States, where phones come unsubsidized, although more and more U.S. carriers are beginning to offer no-contract plans. Usually, a new smartphone will run you $600 to $800 without a two-year contract. Analysts speaking with Marketwatch are predicting the iPhone 5C to be more in the $400 unsubsidized range, and would be pleasantly surprised to see it retail for lower.

How will these iPhones be priced in the United States?
Only Apple knows for now. But if we had to make an informed guess, the top-tier iPhone 5S will likely debut for $199 with a two-year contract. Last year's iPhone 5 will slide down to the $99 range for a two-year contract. And the iPhone 5C will replace the iPhone 4S as Apple's $0/two-year contract offering, since Apple is thought to be phasing out the older 30-pin dock connector of the iPhone 4S.

So… should I buy the new iPhone 5S?
If you're due for an upgrade: Sure! You also can't go wrong with any of the other top-tier smartphones on the market, like the Samsung Galaxy S4 or the HTC One. Wired's Mat Honan put it best: All our best phones are "completely amazing and utterly boring."

One word of advice: Don't buy a new iPhone 5 on contract in the next few days for $200. You will regret it.

When will the new iPhones come out?
If history is any indication, the next iPhone will hit store shelves 10 days after Tuesday's media event. So circle your calendars for Friday, September 20 — meaning those kooky Apple Store campers still have quite a wait ahead of them.

If real, here's what the rumored fingerprint scanner might look like.
(via iPhone in Canada, Apple Insider)