I got the Xbox One version from ShopTo.net here in the UK on Saturday and have played about 8/9 hours of the game so far. The game only installs 162 MB from the disc before downloading a 21.75 GB "Day One" patch that is essentially the full game install as the game only takes up 22 GB on my Xbox One X. There was also another 300 MB patch yesterday.
I like the game but it is very rough around the edges. The ambition on show here is great, especially the attempt at realism from the way you visibly pick things up and open/close doors (you have a physical body unlike most first-person games) to the need to sleep, eat and even bathe! Everything you do increases a stat somewhere, there's no traditional levelling up like other RPGs. Speak to people a lot and get success responses and your Speech stat improves, fight and your Strength/combat skills improve and so on. Fighting is something I've actually been avoiding - I like to talk my way out of situations if I can - although it isn't always possible. One on one fights are fine but go against two or more and it's too easy to die necessitating a reload from the last save point. I have a bow but, for me, it almost unusable due to the lack of a crosshair and the emphasis on realism (wait too long and the arrow fires, judging distances, etc). Sword fighting is better and more fun as you'd expect and the fighting system is fairly deep, allowing for blocks, different types of attacks, counters and dodging.
The framerate on the Xbox One X, which I believe runs at 1440p, is not great though, rarely holding a locked 30 fps outdoors (at least that is how it feels to me). There is very noticeable stuttering when turning and the framerate only really feels smooth indoors or in less busy areas. As soon as a few NPCs appear on screen then the game can feel noticeably choppier. It's never unplayable but if you are sensitive to framerate variation then it may annoy you. There are also some graphical glitches that I noticed such as flickering buildings and objects plus hats/hair on NPCs often pop in just a bit to close and obviously due to an aggressive LOD system. Textures are also not that fantastic for a current gen game and dialogue scenes feature stiffly animated NPCs with poor facial animations and that classic "dead eye" stare. It's better than, say, Skyrim but a long way off the standard set by The Witcher 3. Cutscenes are generally much better but there's still the odd camera glitch or other visual hiccup that can pop up from time to time. Overall, the game looks mostly good but the cracks are there to be seen if you look close enough.
As for the gameplay itself, I am enjoying it; the story and writing is good, the voice-acting mostly OK and it's fun to explore. The world feels believable and there are enough NPCs to make the world feel lived in (even if some of them can get stuck on scenery or caught in animation loops!). However, the game does take a long time to get going and it was 7 hours or so before I even got my own horse. Unlike other RPGs, money is extremely hard to come by, stealing is difficult (not helped by the fact that almost all chests are locked, requiring a clumsy mini-game and lockpicks to open) and even loitering too long in someone's house can have them rushing out to fetch a guard. Even shops have ever-watchful guards so good luck trying to take anything illegally there when the shopkeeper turns away. After hours of playing the game I only have 1.7 G to my name! Everything I stole has been taken off me because guards searched me on entering towns (how they know what is stolen, is a mystery) so everything I have is what I've gained through quests only bar food which is plentiful (just as well as you have to eat regularly).
Despite all the niggles, there's a lot to like about this game. The attention to detail is commendable, the amount of historical information that is given to you as you play via a codex is impressive (if you like that kind of thing) and the game certainly feels and plays like nothing else. On a basic level this is a first-person only Oblivion/Skyrim minus the magical/fantasy elements combined with an open-world survival game. The realism and historical setting though may annoy some people, it may even make it dull for them, but I like that the developers have attempted something different here even if the execution isn't always great. The best thing the developers could do is release a demo post-launch so that people can try it for themselves.