If you're a longtime reader of Cordcutting.com, you've probably noticed that we're fans of Plex. We've ranked it above competitors, showed you how to turn a Raspberry Pi into a Plex client (and, over on The Pi, how to turn one into a Plex server). But what is Plex, exactly? What does Plex do, and what makes it different from its competitors? And how much does Plex cost?We'll answer all of these questions and more below in this new and updated version of our What is Plex? guide. Plex has added a host of new features since our last piece debuted two years ago, and the service has really cemented its place at the top of a competitive (and impressive) media server market. Here's what you need to know.What Is Plex?At its core, Plex is a media server application. That means that it turns local content into streamable content: if you have some videos, photos, and other media on a desktop computer but want to view them on your iPhone, Plex can help you do that. You set up a Plex server on one device and download client apps to a bunch of others, and just like that, media that was once limited to a single device is now available everywhere you go.Plex is the industry leader in the media server space. It's the most established and feature-heavy of the media server applications, which is why we ranked it ahead of competitors like Emby and Serviio in our article on the best media server applications.Plex is also a media center application – that is, a program that makes it easy to access your media. Plex acts as an organizer, content discovery tool, and portal to all of the content on your server – as well as to streamable content from outside of your personal collection. This latter feature comes courtesy of “channels,” or in-program apps.In this sense, Plex is a bit like competitor Kodi (which is a media center application, but not – at least out of the box – a media server) and even platforms associated with devices, such as Roku and Fire TV OS. But because Plex is also a media server, none of these are direct competitors – in fact, Plex even has apps and plugins for Roku, Fire TV, and Kodi, so you can use it within those systems.Plex ChannelsAs mentioned, Plex offers channels that let you watch streaming content as well as your local stuff. The channels are created by volunteers, but Plex grants them official status, so Plex has largely avoided the piracy issues that have been such a headache for Kodi. There are channels for all kinds of streaming content, from Nickelodeon to South Park. There's no channels for the major streaming services, tragically – but since Plex has apps for other media center platforms like Roku, it's easy enough to enjoy both Plex and big-shot services like Netflix on the same device.Plex's Platform SupportSpeaking of platform support, Plex excels there, too. Plex has accumulated a pretty robust list of supported devices and platforms. Among the highlights:Android TV (including Nvidia Shield)Apple TVChromecastComputers (there's a Windows app and an in-browser app that works on other operating systems, including Mac OS)Fire TVKodiMobile (Android, iOS, and Windows Phone)PlayStation 4RokuXbox 360Plex's FeaturesPlex handles a ton of different types of media, including video (movies and TV shows as well as personal videos), music, photos, and even live TV (more on this in a moment). This content can be streamed to any device running the Plex app, including devices outside of your home network.Plex has grown its list of features a bit since the first iteration of our What is Plex? article. Among other things, they've added cloud storage. This means that your server can draw on content you add to one of several cloud storage services, rather than from a device of your own. While it's easy to use everything from a desktop to a Raspberry Pi as a Plex server, it's nice to use cloud storage instead and not have to worry about running a device 24/7. Plex supports Google Drive, Dropbox, and OneDrive.Plex also supports live TV. Plex itself isn't how you'll get the live TV – you'll need an antenna and a digital tuner for that. But if you connect the antenna and tuner to the device running your Plex server, Plex can take that live TV and put it on your server, enabling you to watch live TV anywhere you go. For instance, you can connect an antenna to your desktop computer, run a Plex server on it, and watch live TV on your iPhone.Better still, Plex allows you to record this content in a cloud DVR. That means it's easy to turn live over-the-air TV into on-demand streamable content.Since over-the-air TV is free, of course, the only costs to worry about are the purchase prices of the antenna and tuner and the fee for Plex itself.How Much Does Plex Cost?Speaking of Plex's fees, here's how they work:Plex has a free version, which offers the basic functionality you'll need to run a server in your home and watch your local content on a bunch of different devices. It's quite useful, but it's dwarfed by the premium version of Plex, called Plex Pass.Plex Pass is, of course, a paid service. It will run you $4.99 a month or $39.99 a year. The annual plan is a better deal, and Plex die-hards can save still more by opting for the lifetime plan, which is $119.99.The free version of Plex is perfectly serviceable, but the features that really put the competition to shame are mostly locked up behind the paywall. Live TV support, the cloud DVR, offline viewing, and integration with cloud services like Google Drive are all premium features. So are a host of minor perks, from lyrics for your music to special discount offers.