I tend to believe that an operating system cannot be technically great *and* user-friendly. In many ways they are mutually exclusive goals unfortunately.
That depends on what you mean by "technically great". As grahamperrin already said, in my (not at all humble) opinion, MacOS is both. By the way note that many of the great elders of Unix are today using Macs or Chromebooks for their daily drivers.
What does "great" mean? Uses hardware well, meaning the hardware is abstracted (you don't have to bother learning C-states to get both good performance and good battery life), can make use of very high screen resolutions, up-to-date WiFi interfaces, easy to interface (plug and play) for supported accessories. Stable and secure: doesn't crash, the file system doesn't lose data (even when you shut things down wrong), efficient in its use of the bottleneck of the disk, the file system is encrypted, I can trust the hardware to not easily admit hackers. Easy to develop on, supports all common development tools. I think MacOS fits the description well.
Speaking of a Mac ...
It can't be started up into a direct command prompt.
There are unsupported hacks that allow MacOS to come up without the GUI. They are hardly ever used, because: why? Just let it boot normally, bring up a terminal emulator, maximize the terminal emulator so it takes over all the screen (without window decoration). It gives you the same functionality (all pixels are used for the CLI), but with the flexibility of switching to graphical tools at a moment's notice. My office mate many years ago (another Mac user) had a single very large monitor (probably 32 or 37 inch), which he had mounted in portrait mode, and he used to boot his Mac into running a single terminal on that monitor. And then he only ran emacs in it. He would get into emacs in the morning, and not leave it ever (except for a lunch break). I think his terminal window was about 350 lines tall x 250 columns wide, but with emacs' support for breaking up the screen, he got work done very efficiently. And then, on the laptop's screen, he still had a web browser and the corporate e-mail program.
It supports a tiny fraction of hardware (it doesn't even support the common ThinkPad).
Why would it support other hardware? The hardware that Apple sells you is very good. By co-developing hardware, software and backend systems, Apple is capable of greatly improving product quality at still sane development expenses. We all see how difficult it is to remain 100% compatible with multiple systems, in particular if you don't have direct access and control over the people who develop those. Apple's attitude is: they put effort into creating an excellent product, where all the pieces work really well together, but at a high price. And only if the user is willing to remain in the "walled garden" of Apple's ecosystem. They could instead do what the Dell, Lenovo (ex IBM), Oracle, HP, IBM, and Google, Amazon and Microsoft do: develop a mediocre product at a medium price. But they know that the kind of people who want to be Apple users are happier with excellent products, and perfectly willing to pay the high price. Now, is Apple hardware perfect for all uses? No. As a frequent user of ThinkPads: they have their advantages, and in the server and embedded market, Apple doesn't even play (at least not seriously, the MacMini is not really a mainstream server). But Apple knows that trying to serve everyone would ruin their quality, focus and value, so they don't try.
It doesn't provide a system compiler or a ports collection making it awkward for development.
Xcode is free for download. Matter-of-fact, my corporate issued laptops (from multiple employers) have always had Xcode pre-downloaded; the IT people do that when they prepare the laptops for distribution to engineering groups. On my personally owned home laptop, I had to download Xcode myself (which was a bit of a hassle in the days of 144 kBaud ISDN lines).
MacPorts exist. But I honestly find myself installing very little from there. Most applications are either pre-installed (view PDF, simple picture editing), or available on the web (word/excel/powerpoint = office suites). For python tooling (it's my main programming language these days), I use pip.
Loads of tasks can't be automated via scripts (like the keyring manager) making it terrible as a build system.
It's actually amazing how much CAN be automated, if you search the web. A Mac is chock full of command-line tools, but to use them, I always have to find recipes on the web. I've yet to find good documentation for that kind of stuff.