Yes, even on Windows 10! Like Oblivion, you will probably want to at least install the Unofficial Patch and the Fallout Stutter Remover if you’re getting inconsistent performance, but other than that GOG’s build works perfectly fine. Well, minus a CTD that happened while testing mods. Still, it works as advertised. At least on my rig...
As for the game itself; it’s Bethesda’s take on the Fallout franchise, and while Fallout 3 is a controversial entry in the series (for good reason mind you), it’s still a very enjoyable game if you take it for what it is. Yes, the “3” in the title is problematic when you consider the games’s legacy, as it doesn’t really build on the lore in a way that’s very convincing or consistent. But that doesn’t prevent Fallout 3 from being fun. Really fun. It’s ridiculous at times, and some of the locations are pretty gimmicky, but that’s part of its charm.
Fallout: New Vegas arguably provides a more authentic experience as a proper sequel, but if you ask me Fallout 3 has a more engaging post apocalyptic setting. The story itself isn’t the best in the series, and the black and white take on morality goes against the setting’s ethos, but Fallout 3 remains a good time even after all these years.