I've been playing D&D since 1978. 5e since it came out (currently playing 2 campaigns and DM'ing one, so 3 sessions/week).
BG3 is a *very* good translation of the rules to PCRPG format.
And the knowledge checks are awesomely done so far. Very seamless. The info you get can vary based on how well you rolled behind the scenes on Arcana, Religion, History, whatever.
Tons of dialog choices that depend on class, race, background, etc as well.
It's super early access. Only Act 1 is done. Only 6 classes available right now (fighter, ranger, rogue, cleric, warlock, wizard). 6 more coming. Race choices are human, half elf, elf, drow (separate from elf), tiefling, halfling, dwarf, and githyanki. At least 2 subraces for each one except humans and githyanki. No gnomes, half-orcs, or dragonborn yet.
Fairly buggy.
Don't get the game now just to play BG3. Get the game now if you want to be a part of making it awesome later. You will be restarting often. There will be changes. There will be save wipes. And so on.