While the name might be confusing, the Xbox One is the third Xbox console and a powerful new platform for video games. Combined with the new Kinect and a number of major exclusive franchises, it's a huge leap forward into the new console generation.
The main user interface is extremely easy to use and figure out. While certain hardcore users may prefer a more "classic" interface for gaming consoles, this interface has been designed specifically to make things easy for a casual user.
The new Kinect is more powerful and somewhat easier to use than the previous version, which is great most of the time (see the "Cons" section). The player can navigate throughout the console and its menus at any time using either voice or motion commands. It may not be perfect, but it's a step in the right direction.
The one thing that I like best about the Xbox One is that the player can get from any game or application to the menu system and back quickly and easily. I don't have to quit an application to change settings or check on how far along my download is.
After the failure of HD-DVD at the hands of Blu-ray the Xbox 360 was left with a slightly inferior feeling. With the greater increased presence of high-resolution Blu-ray movies, this was going to be an even greater problem for the next generation of consoles. Fortunately, Microsoft made the wise decision to include a Blu-ray player in the Xbox One.
This will change with time, but part of the reason for buying a new console is for the exclusive games. Both the PS4 and the Xbox One have some true exclusives (meaning they are only available on one console), but so far there are too few games to justify buying a new, expensive console.
For the average user this is not an issue, but I have intimate knowledge of the lack of good development tools. For big publishing companies this isn't much of an issue, causing hours of tedium but their knowledge base can eventually figure things out. But for small, independent developers this is a serious problem. I expect many more independent games to come out on the Playstation 4 instead of the Xbox One.
The reality is that the Kinect is still a poorly designed tool that can be extremely difficult to use. It is almost certainly because of this that there are few games available that make use of the Kinect in any interesting way. Plenty of games try to include it, but it seems to be thrown in to satisfy some arbitrary request from Microsoft.
This is a problem that the Xbox 360 had and still continues with the Xbox One.
The advantages that the Xbox Live brings comes with a price in the form of an annual fee. The fee isn't particularly expensive considering the benefits that come with it, but I've always wondered whether or not it was worth the cost.
The other problem is that after paying the annual fee, the player is subject to seeing additional ads that, usually, are completely irrelevant to gaming. It definitely detracts from the experience, especially considering how expensive the annual fee is already.