I do highly recommend it. It is not without it's flaws, or things that can be improved when the modding scene kicks into gear. But there are so many improvements over Fallout 3. Or Skyrim for that matter, which improved on FO3. The crafting system borrows from and improves a lot on Skyrim. The game even has less bugs that I've noticed than is typical for a Bethesda new release. The feel of the game is better. The towns, while still smaller than they should be, are a good bit bigger and make more sense than in FO3 or New Vegas. Places like Concord and Lexington have a mixture of homes, shops and businesses, where as places like Greyditch or Bigtown were clearly made by just copy pasting a few homes and adjusting the contents of them.
The size of the buildings is a lot more claustrophobic as well, making gunfights a more tense issue as by the time you see them, ghouls or mutated critters are generally in your face. It feels a lot more realistic. Combat itself is a lot better as well. People react in believable ways to be being hit. Human enemies hide behind cover and try to shoot out of it without exposing themselves. Ghouls charge en masse without regards for personal safety. Animals will often make hit or run attacks, or mob you in groups.
So far my biggest complaint is that the main quest line is probably to compelling, and at the same time, gives you little enough as the player to care about it. I won't spoil anything obviously. But you only get to spend a little time with your spouse and son in the pre-war scenes. Enough to get a bare feeling of who these people are, but not really to feel a connection to them. Then the bombs fall and everything is moving on briskly. When you get into the game proper, if you were in character you should be pursuing the main quest line without delay or side tracking. But the nature of the game means that people are always going to be asking you to do stuff for them. There's always going to be interesting places to explore and in general playing the game interferes with the main quest line, rather than supports it.
I've only put in 16 hours so far, and really only barely scratched the surface. But I do highly recommend the game, without any serious reservation. If you are a fan of Fallout.. Well it's a no brainer you probably already have it or are planning to buy it. If you never played Fallout before it's a good place to start.