I visited Davis. The department had a quite friendly atmosphere among the grad students. I actually met someone at the UC San Diego open house who planned on turning them down for Davis even though UCSD had more resources and perhaps objectively better research because of the difference in terms of how sociable the grad students are. For what it's worth, I don't think there's much of a difference in how friendly grad students are anywhere, at least among the schools I visited.
The physical building for the physics department is rather average in terms of middle-aged academic buildings. A recent space crunch should be resolved very soon, as right now they're sharing with geology which is getting a new building (first year grad students had offices in a trailer in the back!).
The town of Davis is flat and filled with gazillions of bike paths and bikes. It's a fairly standard college town surrounded (immediately) by farm land, but within easy reach of nearby metropolises (San Francisco, Sacramento) and the Sierra Nevada (Tahoe is 2 hours away). Apparently it gets uncomfortably hot (but dry) in the summer, but in the rest of the year it's warm nice California weather.
Students did seem to spend a lot of time worrying about the quals. In particular, it seemed that they might forgo a possibly significant amount of research during the first summer to study instead for a month. I don't know if that's because the quals are particularly difficult (I doubt it: as at most places, most pass at Davis) or due in part to Davis being a lower ranked school than other places I visited, possibly with less strong students. But it's not unheard of for well-prepared students to pass immediately, either.
I do know that the caliber of students (and the number of applications) at Davis has increased dramatically in the past few years, as well as the quality and size of the physics department. It's definitely on an upward trend if you look at rankings over the past few years.
I didn't pay much attention to astronomy or experimental physics at Davis since those aren't my interests.