Overall, I'm thoroughly enjoying my wasteland experience. There's of course plenty to grumble about (not only bugs, weird performance issues, but mechanics) but the scales shift far more in favor of good, than bad.
Most of my quibbles are based on a personal bias. For example, I'm not completely on board with combat becoming more fast paced and FPS-esque. I'm used to spending almost as much time on my Pip Boy as I am actually laying waste to my enemies. Not anymore. The new system, with hordes of assaulting enemies, VATS not completely stalling time, and actual functioning non-assisted shooting is just a new direction. A lot changed from Fallout 2 to Fallout 3 so I understand, stuff changes. I think my biggest gripe in this area is the loss of VATS. VATS just doesn't play as big of a role, and with time not stopping and only slowing I've found VATS to be a little buggy and difficult to ease efficiently. Sometimes I just opt to aim down the sights and unload, and that's a shame.
Perhaps my biggest gripe is the overhaul of how you communicate with others. I am a fan of a the Mass Effect series but I don't like its four speech options and your character actually talking being in the Fallout universe. I feel like I have both less conversational options and less of a role-playing experience when your character actually talks. I guess I can't be Bostonian with a Irish accent and a drinking problem can I ma? I'm sure there will be a mod to rectify this (and probably VATS too) so that's good.
Now, one of the greatest part of the game is how good the mods are going to be. It's a game that has so much potential for brilliant and absolutely amazing mods. It's everywhere you look.
I really love the big cities, the voice-acting, the characters, the building your own places, the in-depth gun modification, and all of that. I've always been a hoarder in games and the fact that everything is useful now I can feel like my hoarding mentality is finally worth a damn. I'm about eight hours in and I think I've finished maybe... seven or eight quests? I've mostly just been looting, hoarding, and building. I like what's going on, I like the story, and overall I like the mechanics.