UA installed a good Y product on its MAXes. For a 737, it’s as good as it can get.
What I don’t like about the 737 is its low windows, narrow fuselage, and I’m personally not really a fan of the bins on the Sky Interior planes. But these issues are definitely not unique to UA.

**Why I don’t like the new bins. Of course extra capacity is more than welcome. These bins have this curved design to invoke a feeling of more space, but as mentioned earlier the plane is tight anyways. Having to push 50 pounds of bags up to close the bin isn’t a very good design choice IMO. The air vents are seemingly worse than the past generation ones. And how does an Aisle passenger interact with the PSU?