Took a spin with 10.14 today...
short version: Not recommended!
I'll note the positive first:
The business Apple started with 10.13 making downloading the installer app difficult has been abandoned! Very welcome!
You can simply download the complete installer through the App Store again. No more editing your hosts file and downloading separate packages and all that.
However...
Bugs in the installer again... Or we can just come out and say it in plain language: Apple looks to be blacklisting many of their pro model machines with this installer. Many of the models with fully supported hardware and the pro configurations that they don't even have new equivalent models available with.
Dosdude1 is on the scene again with installer patches.
The Apple server was actually crashing when I tried to download the installer initially and the Dosdude1 tool made an easy workaround for it.
I tried back later again (and to see if it was the same installer file set) and it just worked. Full installer downloaded with none of the partial file business and spoofing with the hosts file workarounds.
The recovery partition doesn't seem to work on these models I've tried so far: 6,2 8,2 9,1
So far I've noticed that the trackpad preference panel in System Preferences will not recognize the trackpad (even though it seems fully functional). This means no setting preference options (taps, scrolls, gestures, etc) from default without manual terminal commands.
Note that this is all with the APFS disk format on SSD's. These machines have the current firmware supporting APFS.
Just mundane poking around - browsing the hard drive, browsing the internet with Firefox, working various preference panels - I find 10.14 to be very noticeably slow and laggy. Not just the extra long booting either. It genuinely slows down your machine. (The 3 I tried include literally the 2 flagship models of Macbook Pro both outfitted with SSDs.) In contrast, 10.6.8 boots before the spinning status indicator can even display! 10.13.6 boots in 5 seconds but is actually noticeably faster than 10.6 in operation on the same machine. 10.14 is an absolute disaster so far.
And this is where I stopped!
Obviously there is at least some functionality. Maybe the nuts and bolts of the system are intact and audio apps may just work. I haven't tested every version machine yet but the gen 8 and 9 machines are the top flagship machines Apple has ever (or likely will ever) produce. These little nickle and dime bugs are shockingly sloppy for the likes of OSX. This isn't supposed to be a Microsoft-like product. Not a good look at all for Apple here unfortunately. I'm going to wait until at least a .2 update before even considering another trial. Don't go for this OS unless you have a spare drive volume to experiment with it on and have time to kill.
The dark theme looks cool. Was looking forward to that kind of. Way too many glaring bugs in critical functions to consider that right now though.
Have a full Carbon Copy Cloner backup clone ready to roll back to if you even consider this OS version! You've been warned.
*edit
I'm told that the 10.14 installer should be pointed to a HFS+ formatted drive initially (a hard requirement for the 10.13 installer) even though you may have already been running 10.13 in APFS and even though you have the APFS firmware update. I haven't doubled back and run a trial of that yet.
The slowness is the most unexpected and disappointing thing. Services plain not working is no less troubling of course. And here I thought this one was going to be all happiness and light! Reading it the riot act instead. Thinking out loud though... Could this be fallout from something gone wrong with the install related to not really supposed to be installing to an APFS formatted drive? The slowness kind of felt like using an old machine with a spinning drive but I'm just speculating now.