I saw this last night - and I'm still sorting it out.
I am a huge PT Anderson fan. And I think I'm let down in a way.
I won't give away any spoilers.
The only way I can describe it is this:
Imagine you're really into puzzles. But specifically, you're REALLY into puzzles made by a particular puzzle master (no pun intended). So when you hear he has released a new puzzle, you get very excited, and as soon as you can, you buy it. As you open the box and begin to examine the pieces, they are among the most beautiful pieces you have ever seen. The edges are perfect, the colors are so real you think you could fall into them and smell and touch and hear what you see. You take the pieces out one by one, savoring each one and it's inspiring beauty. You begin to assemble the pieces and though several might fit together and start to form a larger scene, you soon realize that the pieces are all gone, and the puzzle is left with holes.
You can still appreciate the pieces, and how some of them first perfectly together to form landscapes and scenery and one group of pieces may intersect with another to give you an even more vibrant vista - but it still stops where you think there should be more.
And that's the best I can describe it. The performances are powerful, gritty, and real. The cinematography is nothing short of perfection. Some of the scenes are so perfect I could cry. The soundtrack (thanks again Jonny Greenwood) is thick and mystic. And yet... I was left wanting. Wanting for more continuity. Wanting more connections. Wanting more motivations for why characters did what they did. Wanting more depth and history.
On balance I was still entertained, and being the visual filmgoer that I am, I was mesmerized. It was no Magnolia. It was no There Will Be Blood. It was only more than Hard 8 because of the visuals.
I'm not really happy about it, and not really sad. Just... still putting the pieces together.