If you don't know what to think of them, then my guess is that you won't use it much, letting it collect dust, like Metal. Only if you know exactly what you'd use it for ahead of time, so that you could justify the cost, would I buy it if I were you.
Those boxes have all kinds of features and capabilities, but most people are unlikely to use the vast majority of them. Most people will use a box like that for only one or two things. I would guess that accessing Netflix and playing personal digital movie collections (from something like Amazon or own personal MP4 collection) are the only things that most people would consistently use a box like that for. If those two things are appealing to you, you might consider it.
Also, that's a pretty new and powerful box. In fact, it has 8 cores, 2GB of RAM and can handle 4K video. If you don't even know what you'd use it for, then it may be more power than you need and, thus, more money than you need to spend. You can get cheaper boxes that'll likely be sufficient for your needs. Buying a cheap product to see if it's something that you would use, before blindly buying an expensive one, might be smarter.
If he's really your friend, he'd let you borrow it first and play with it, to see if his price is worth it to you. If he's not willing to do that, then leave it alone, since that's a bit suspicious, especially since it's a very new model (Amazon doesn't even have any reviews of it yet), so there could something that he's not telling you.