I’ve been fortunate to have been offered an development kit for the Apple TV Gen 4 and have been using one for the past month
The Remote is a Lightning cable, and the box does come with a long Lightning cable, however the Apple TV is a USB-C device, which is kinda odd, giving that it would made more sense to use just lightning since tvOS is just a slim down version of iOS. Maybe this is a stealth plan from apple to prepare everyone to USB-C on an iPhone. Anyway,I was forced to buy a 20€ cable to connect the box into my computer, so I could write apps and reset my Apple TV (a necessary step to upgrade the Apple TV to upgrade to the public version of tvOS and access the App Store).
Writing apps is just like writing apps for iOS but I did find some problems migrating touch code into Apple TV, since you don’t have a multi touch device. In terms of an set top box, is quite nice. Netflix and Plex work great, and apps do make sense when using on a tv. However is the small things that make some tasks on Apple TV annoying. For instance, you have to to enter you password into every service, and you have to use an on screen keyboard that works worse than my Samsung TV one (e.g. you can’t scroll letters past right to loop around to the left most item) but you have the option to set up the TV by touching an iOS device. The remote is undoubtedly a flawed design. You can’t figure on the dark in what orientation is in your hand. If you touch the remote while using another input, the Apple TV will wake up and switch your TV input to it. Games are required to being playable using only the command, however the remote has only two buttons and the touch pad available to apps, making playing games ranging for weird to plain unusable. Siri on your remote may be the answer to a smart TV, but is not available in Portugal, nor you have the chance to use the US version.
Clearly there is potential here (notifications, multiple panels within a video feed), but this is the iPhone 1 of Apple TV.