3G vs. 4G Wireless - What is the difference? First off, the "G" stands for a generation of mobile technology. Each "G" generally requires you to get a new phone, and for networks to make expensive upgrades. The first two were analog cell phones (1G) and digital phones (2G). Then it got complicated.
Third-generation mobile networks, or 3G, came to the U.S. in 2003. With minimum consistent Internet speeds of 144Kbps, they were considered mobile broadband. There are now so many varieties of 3G, though, that a 3G connection can get you Internet speeds anywhere from 400Kbps to more than ten times that.
New generations usually bring new base technologies, more network capacity for more data per user, and the potential for better voice quality, too.
4G phones are supposed to be even faster, but that's not always the case. There are so many technologies called "4G," and so many ways to implement them, that the term is almost meaningless. The International Telecommunications Union (ITU) tried to issue requirements to call a network 4G but they were ignored by carriers, and eventually the ITU gave up. 4G technologies include HSPA+ 21/42 (HSPA was for 3.5G), WiMAX, and LTE (although some consider LTE the only true 4G of that bunch, and some people say none of them are fast enough to qualify.)
There's one thing for sure though, each generation offers faster Internet speeds than the last, on the same carrier. Sprint's WiMAX 4G is almost always faster than its CDMA 3G. But AT&T's 3G HSPA can be faster than MetroPCS's 4G LTE. You can rely on speeds to move up within your carrier, though.
PC Mag runs a yearly Fastest Mobile Networks contest, and in last year’s test, they found (quoted from the magazine) “that Verizon's 4G LTE network was the fastest, followed by T-Mobile 4G HSPA+, AT&T 4G HSPA+, Sprint 4G WiMAX, MetroPCS 4G LTE, Verizon 3G, and Cricket 3G, with Sprint coming in last. As AT&T and Sprint put out their LTE networks, they are expected to be competitive with Verizon's LTE speeds.”
You have to ask yourself when it is right for you to get 4G. Right now the mobile carriers are still building up their 4G networks, so first off, you’ll need 4G coverage to appreciate a 4G phone. Of the national carriers, Verizon and T-Mobile have the broadest 4G coverage. AT&T currently only covers about a quarter of the nation’s population.
Sprint is in the middle of switching 4G systems, from WiMAX to LTE. The two are not compatible with each other, so you must check coverage in your city for the specific variety of 4G you're buying.
If your data plan is not unlimited, you better watch out for the amount of data you use, because it's easy to use up a lot very quickly with 4G.
If you have a 3G phone and the clogged-up networks frustrate you, 4G may be the solution. You'll be switching to a different, less-trafficked network for your Internet data. 4G won't solve any dropped call problems, though, because all calls will be made over 3G networks until carriers switch to voice-over-LTE during the next few years.
If you want to future-proof yourself, get a 4G phone. 4G coverage is only going to get better, and that's where the carriers are spending most of their money right now. As we move into 2013 and 2014, some carriers will even try to switch subscribers to 4G-only phones which make voice calls over the LTE network.
However, as of today, if you live in an area that doesn't have 4G coverage, there's no advantage to a 4G phone. In fact, you'll have serious battery life problems if you buy an LTE phone and don't turn off 4G LTE, as the radio's search for a non-existent 4G signal will drain your battery quickly.
I have attached several maps for different carriers showing the international coverage area for 4G. When traveling outside of those cities, your phone will automatically switch to 3G.