So, I'm about 40 hours in, and enjoying the hell out of it, though it's got it's flaws.

Things I love:

• Crafting - now all the junk in the wasteland has a use. Being able to customize my equipment to my playstyle is awesome.
• Stealth - Now it's vastly less overpowered than it was, but it's still very effective and useful. Now instead of just maxing the skill and sneaking through everything, you have to be smart with it, and that's a good thing.
• Combat - feels much more tactical. At level 25, I'm not an untouchable god. Being able to sprint, execute crits-on-demand, and not having armor that allows me to ignore incoming damage feels right- I have to fight more carefully to be effective.
• Power Armor - Much better having limited time I can use it, allowing me to strap in and go god-mode for those really crazy fights.
• Settlements - building something in the world feels good. I love helping out settlements, helping them build their necessities, and seeing them grow. Being able to build whatever I like for a fort or house is bonus points.
• Legendary enemies and gear - more gear variety- hurrah! This really does a good job of offsetting the loss of "gear hunting" importance from crafting. Even better, I can take mods off similar non-legendary weapons and put them on new ones.

Things I'm disappointed by:

• Dialog choices - The old written dialog was much better. I don't know what the hell my character will say when I choose a dialog option, and I'm not a fan. Also, eliminating solutions based off skills (science, repair, etc) and reducing it to persuasions strictly off charisma feels like "dumbing it down".
• Quests - So far, the quests have been a lot less complex than what we got in New Vegas. Lots of "go to location X, and kill the tagged boss" quests, and very little approaching the intricacy of quests we got in prior entries.
• The UI is pretty unintuitive - especially assigning settlers to tasks is incredibly painful to keep track of if you invest in building settlements, and figuring out how to set up a radio beacon the first time is painful. The "tutorial" settlement quest never even mentions assigning settlers to jobs, or even junking existing structures in the settlement for materials.
• Less information - we're missing a bunch of useful information about how crits and armor work, for those of us who really like to wring the most out of our builds.

Things I've got mixed feelings about:

• The perks-only character system. I don't dislike the idea, but it feels like development has slowed down a bit too much- to the point where choosing between combat effectiveness and other options feels pretty limited.

It feels like a great improvement from a combat standpoint, the "sandbox" options added with crafting are incredibly cool, but a big step backwards in the dialog and quest aspects. I miss the complex choices between factions that we had going on in New Vegas, and the varied options we had for solving things. Hopefully the DLC will see them stepping up their game in these areas.