(All still true now in Nov 2018)

I am an unashamed Bethesda fanboy, and this review will evaluate the game in comparison to Skyrim and Fallout 3.

Graphics: They are better than either Skyrim or Fallout, and I found them perfectly satisfactory. I was playing with the distance settings maxed out and everything else set fairly low to compensate. I do not come to Bethesda games for the graphics anyway, so this is all I have to say.

Character system: All skills have been removed. Instead there are the SPECIAL stats, and perks. Some have criticised this as dumbing down the system. Perhaps, but in my opinion it plays better. The requirements for Fallout 3 perks were a confusing mess, an inconsistent combination of skill, SPECIAL, and level requirements. Now all the perks follow a clear pattern, making it much easier to plan your character. The new system also has the side-effect of better balancing the various SPECIALs. Endurance is now retroactive, so you don't have to raise your endurance early on. Intelligence is no longer OP because there are no skills. Charisma is no longer useless, because without the speech skill it has become the determinant of persuasion successes. My only gripe here is that some perks I consider essential to my game have high requirements - namely, the Local Leader perk, but also the hacking and lockpicking ones (in Fallout 3 most important gameplay elements could be unlocked through skill increases). I look forward to a mod that will let me build supply routes even with a low Charisma build.

Gunplay: The guns feel much much better than Fallout 3, making the gameplay more dynamic, perhaps even more than Skyrim. I don't want to use VATS anymore because the guns are so fun to shoot. My gripe here is that critical hits are only possible via VATS. I also found that, on Very Hard difficulty, I didn't have enough ammo to maintain my preferred energy-weapons-only build. But the new character system means I don't have to sink skill points into this - the related perks are for "rifles vs pistols" instead of "energy weapons vs guns", so my character was not harmed by the lack of ammo.

Enemies: Enemy behaviour and animations have much higher fidelity than Fallout 4 or Skyrim. They no longer simply walk towards you and attack as soon as they see you. As an example, mirelurks now use their armor intelligently when moving towards you and engaging, tilting their body to keep their head covered. Ghouls dodge and weave around, and move slowly until they are close enough to perform a lunge that I still don't expect as much as I should.

Exploration/Dungeons: The exploration gameplay I rely on Bethesda for returns in all its glory. The game is designed for the new gen consoles, and the devs have felt free to use more RAM when designing dungeons/locations. This has produced an immense improvement in location variety and quality. In Fallout 3/New Vegas, elevators were always load points, because the devs had to subdivide large dungeons (like Vaults) into several interior cells. In Fallout 4, most elevators are now real elevators, and most dungeons fit into a single interior cell. This makes them feel more immersive to explore, and loosening the restriction seems to have let the devs invent a greater variety of locations. This goes double for exterior locations. In the previous games, memory restrictions meant nothing particularly exciting could ever happen in an exterior cell. Now, whole dungeons are found outdoors with no load points. These are much more interesting to explore, and even more varied than the interior ones. In Skyrim and Fallout 3, any two dungeons using the same tileset (e.g. two vaults or two dwemer ruins) felt basically the same. In Fallout 4, I've fully explored about 1/3rd of the map, clearing every dungeon I've encountered, and I have yet to have that feeling of monotony that was so common in the previous games. You spend a large amount of your time exploring dungeons/locations, and the variety adds up to a large increase in fun :D

Story/Dialogue: I've been too busy exploring to say much about the story, but the initial parts of it have been better than I'm used to. The protagonist has more of a backstory than usual, which is a tradeoff - less player freedom in exchange for the ability to offer a more finely tuned story. The voice acting was top-notch. The biggest change is, of course, the voiced protagonist. I am happy with the voice so far. My gripe is the new dialogue wheel - it is more like Mass Effect, which is not BAD, but I prefer to know exactly what my character is going to say. However, this has already been fixed: http://www.nexusmods.com/fallout4/mods/1235/?
Hooray for mods!!!

Workshop/Settlement system: This is the major new addition. Building is fun - pieces snap together like Lego. It's much like a greatly simplified version of the creation kit, but available in-game. There are quite a lot of unlockable workshop locations in the game, and converting them all to settlements feels like I am slowly conquering and pacifying the wasteland. Previous games could never deliver on that, since the enemies in every location would respawn eventually. The happiness meters are quite unpredictable/buggy, which I hope will be fixed with patches or mods. The settlements also have fairly strict limits on the total amount of things that can be constructed, but these are already possible to remove with mods. My major gripe is that all the settlement locations come with some stuff prebuilt, not all of which can be removed. I would much prefer to build on a blank slate, and look forward to mods that will give me that opportunity. Weapon modifications have, in my opinion, improved the game. There is now a reduced variety of "base" weapons/armor, but each has a large space of possible configurations due to the crafting system. This has the major advantage that legendary (read: "enchanted") items stay useful for longer, since at higher levels you can just install higher level modifications instead of having to replace them with a whole new item. Finally, the workshop and crating stations in a single location have a shared inventory, which is really convenient while crating. Connecting settlements via supply lines also lets you use the resources in one location to build things in another (but does not fully share their inventories) - this is why I consider the Local Leader perk to be vital. The workshop menu has a "store all junk" button, which is a huge help given that I usually return from loot trips with 100s of junk items. Junk is useful now, so you'll want to carry basically everything back from a dungeon. Item weights seem to have been rebalanced - I find that picking up literally everything seems to encumber me slightly slower than piccking up all non-junk items used to in previous games.

In summary, I consider Fallout 4 to be strictly better than Bethesda's previous offerings. I don't think I can ever go back to Fallout 3.