The time has finally come. The planets are aligned. Apple's iPhone 5, and iOS 6 are both available now. But before you rush to get in line with everyone else to buy the phone, here's something Apple isn't advertising. "4G" doesn't necessarily always mean 4G.

That all depends on your wireless carrier's 4G coverage. The concept of 4G itself is fairly confusing to us, and apparently, we can blame that in part on the carriers. From Verizon and AT&T to Sprint and T-Mobile, claims of 4G access across the board sometimes amount to little more than snake oil. So what exactly is real "4G," and who's got the best coverage?

Types of "4G" 

4G

A 4G-enabled device is basically any device that pulls in wireless data faster than any 3G device. There are three major 4G standards: WiMAX, HSPA+ and LTE. Generally, HSPA+ and WiMAX run at the same speed - about 3X faster than 3G. LTE leads the race at 10X 3G speed.

Got it? Well, things aren't even that simple. To complicate matters for us, the four major carriers all define "4G" in their own way. Verizon's 4G platform is LTE.T-Mobile's is HSPA+. AT&T uses HSPA+ and LTE. And Sprint's step up from 3G is WiMAX.

HSPA+

HSPA+, or "Evolved High-Speed Packet Access", is essentially a super-charged 3G network, about 3 times faster than 3G.

WiMAX

WiMAX, or "Worldwide Interoperability for Microwave Access," is probably the least known of standard of 4G, and right now Sprint is the main carrier we know of using it. Sprint claims its 4G speeds are up to 10 times faster than its 3G speeds. Of course, that could be hyperbole, but WiMAX is noticeably faster than 3G.

4G LTE

4G LTE, or "Long Term Evolution", is the newest fastest genre of the 4G network. Reportedly, carriers claim it's up to 10 times faster than 3G, and apparently, that might even be a low estimate. LTE is so fast that download speeds can rival cable or DSL.

Granted, LTE isn't a sure-thing replacement for your wired Internet connection, but it comes pretty damn close.

Wireless Carriers:

Verizon

Verizon covers the most communities with their 4G LTE service: 370 cities and counting. However, just the company's coverage map shows, if you're in the middle of Kansas, prepare to be very envious of the east coast.

That's the biggest drawback with Verizon's service. If you're not in a 4G LTE coverage area, your service falls back to 3G speeds.

AT&T

AT&T loves touting its 4G coverage (275 million customers), but there's a fundamental problem with that claim. What AT&T describes as 4G is technically an HSPA+ network, or a turbo charged 3G (about 3X as fast as 3G). Their 4G LTE network is limited to approximately 50 major metropolitan areas, but they plan to double that number by year-end.

AT&T does have a better fallback plan for areas not covered by their 4G LTE service. AT&T customers without 4G LTE coverage or a 4G-capable device connect to AT&T's HSPA+ network.

Sprint

Sprint's HSPA+ service is pretty much their top of the line. Just recently Sprint started rolling out 4G service in a few (6) areas. Although, be prepared for the same confusion AT&T has caused with its "4G" network claim. Sprint's calling both its WiMAX and LTE "4G."

T Mobile

Where's the T Mobile 4G coverage map? Exactly.

T-Mobile is the slacker of mobile carriers when it comes to carrying 4G, and currently has no 4G service - their entire network is HSPA+. When they'll begin to upgrade is anyone's guess.

So be vigilant. 4G is certainly the new buzz-term for smartphone makers and carriers alike, but clearly, "4G" isn't always 4G.