Verizon says that LTE Advanced works by combining the multiple bandwidth channels your phone can use into what's effectively one bigger, faster pipe to your phone. "Typical" download speed will stay around 5 to 12 Mbps, but combining two channels can net peak speeds up to 225 Mbps -- that's a lot faster than most home broadband, let alone what you'll usually see on your smartphone. The carrier also says that it can combine three channels for speeds close to 300 Mbps.
Verizon's estimates for "typical" speeds seem low to us, but there's no question that two- or three-channel speeds are significantly faster than what the carrier currently offers. Even if Verizon only reaches half of what it promises for peak speeds, it's a pretty significant boost over the status quo.
It's not at all clear what circumstances will let your phone take advantage of these higher speeds, however. Verizon vaguely says that it'll kick in "when you need it most," typically under conditions with "big data use." Still, the potential for faster download speeds can't hurt.
To take advantage of LTE Advanced, you'll need a relatively recent smartphone -- Verizon says Samsung's Galaxy S6 and S7 are compatible with the service, as well as various Moto Droids and iPhone models. You can see the full list of compatible devices here, and the full list of LTE Advanced cities can be found here.