It all depends on your needs. For the purposes of this guide, all of the security cameras we test are wireless in the sense that they transmit data via Wi-Fi.
However, some of the cameras need to be plugged in to an outlet to work (i.e. wired), while others are battery powered (wireless). If you're planning to install a security camera indoors, then a wired camera is probably the better option, as there should usually be an outlet near where you want to place it.
If you're looking to place a camera outdoors, then the wired vs. wireless debate is a little different. The advantage of a wireless camera is that you can place it virtually anywhere; however, it also means you'll have to recharge its battery occasionally. By contrast, you're more limited as to where you can place a wired camera, but you never have to worry about its battery running out of power.