I'm assuming most of the reviews here are from early access, here's one from someone who did not play early access and has also not played any previous games in the series.
This game is very good. It's expansive, challenging but not unfair, and there's a good amount of character and party customization. It's the most RPG-y RPG I've played in a long time.
You'll travel the open world, come across riddles, puzzles, enemies and dungeons - some of which will be too high level for you. There is no level scaling and the world is crafted in a way that you're going to want to backtrack often to try and kill that boss you found who one shot you 10 hours earlier. And that's awesome. You're going to be battling your way through dungeons, barely surviving by the skin of your teeth and have to make runs back to town (actual runs, no instant click travel here) to restock on supplies so that you can continue. And that's awesome.
It's not going to be for everyone but this is a really solid, lengthy and replayable RPG with lots of substance that's built on its RPG systems and its gameplay rather than a story or dialogue choices or any of the usual modern stuff.
The only con is performance. Performance is poor in some places, and loading times especially are poor. This is exacerbated by the fact that the game freezes in the background, meaning you have to sit through the 30 second-1 minute load screens. This can get very annoying because you will often be making trips back and forth to town and there's a loading screen each time. The game also doesn't exactly look amazing and the dialogue and story are generic and half-♥♥♥♥♥. But from what I understand this is a game made by a small team mostly as a proof of concept to get this series back up and running, and it did what it set out to achieve and then some.