Some services go above and beyond, including extra capabilities that improve the experience. For example, a few offer disk courier services for bulk uploads and restores via an external drive that the company ships and manages. A couple of these services throw in a local backup component, too. If you go that route, you should take a look at our roundup of best external hard drives. Some of these services can even track your device's location and let you remotely wipe it in case it's lost or stolen.
5K Player also features DLNA server playback so videos you grab can be watched on any devices on your home supporting DLNA network; it supports AirPlay for quick playback to supported devices. Pick a video in the library and you can do a quick conversion to MP4, MP3, or even ACC (an audio format preferred by iOS devices). The player didn't like playing back the overly large 4K file though and experienced buffering issues—VLC didn't have any problem with the same file. Ultimately, there's a lot to like about 5K Player, from the price to the features, especially if you look at them as extras on a downloader. But the interface and playback issues may have you looking elsewhere.
The DVDVideoSoft system gives you free downloads in just about any style you might need. It’s an easier YouTube video downloader that consists of only three different steps. The system is older than some because it’s more than ten years old and it provides some of the best quality you could want. It’s available to be used on both PC and Mac computers, which gives you the level of versatility and flexibility that you’re looking for before you even get started. Plus, you can get a range of different options or different formatting features to the videos that you want to download.
BackBlaze doesn't have an offline component, so you'll have to handle that yourself, but it's by far one of the most affordable options on the market. Accounts are $5/mo (you get a break if you pay up front for one or two years), and you can add more computers to the same account for another $5/mo. You can read more about Backblaze's pricing options here.