4G devices are expected to flood the market, advertising blazing download speeds and technology that rivals some notebook PCs. But as with any technology, there are upsides and downsides.

Most users love their devices to function faster than before. Many now see streaming videos as essential, rather than a frill. But not all is well with the new technology featured in smartphones today.

Surely 4G smartphones stand way ahead with blazing fast downloads, fast video streaming, better file syncing and other activities requiring robust speed. But how fast can it get? More users hopping in to the 4G network is expected to push down speeds in near future, though Verizon in particular has touted its readiness for an influx of Android and iPhone users.

Faster speeds make tethering a smartphone to the computer more useful. But be ready to pay extra bucks for the privilege. That said, the Wi-Fi capabilities of many phones allow for using that network for calls -- a good way to reduce the number of voice minutes used, and with it the bill.

One of the biggest negatives that can affect your 4G smartphone experience is the poor battery life. Smartphone battery life tends to be shorter than 3G smartphones, largely because 4G phones tend to carry multiple antennas and transmitters -- one for the phone network, one for Wi-Fi and a Bluetooth connection. More power consumption means batteries have to be bigger and heavier, but those are starting to reach their physical limits. Nevertheless, having a heavier 4G device and acceptable battery life is much better than a light smartphone which dies in a couple of hours.

Another issue is whether your carrier offers a 4G network at all. Many say they do, but not every service provider has completed its network upgrades. Sprint, in conjunction with Clearwire, is still building out several markets. Verizon claims to have covered most of its territory. AT&T says they do as well, and T-Mobile claims it has a 4G network in place already. But whether your smartphone gets the speeds advertised is highly dependent on where you are.

That network strength affects things such as voice quality as well. AT&T, after introducing the iPhone, also became the butt of jokes after many customers complained that the phone couldn't do what it was ostensibly built for -- make phone calls without dropping them.