If you're into (classic) RPGs/Fallout or good stories/writing. People who prefer FPS games complain about the combat systems. But it's not like "teh best game eva" - it depends on your taste and it's not a groundbreaking game in itself. It's just semi-iconic because Bethesda games are very popular, and FNV is like the craft beer to the natty lite of big Bethesda games. Superior and smarter with less of a budget. And it's the last best Fallout game. So people rave about it for a bunch of reasons, but whether you'll like it depends more on you.