Loud and sometimes vibration-inducing. But this seems potentially feasible to mitigate through sound insulation (both on the train and on the buildings; frankly, our buildings should have a lot more sound isolation than they do).
I live next to a bridge in NYC that carries trains, so I have experience here.
The set back from the bridge to my building is about 5-10x as far from my window as an elevated train line running on an avenue would be.
I have new windows, plus a second set of quiet windows installed within the windows. Essentially quadruple pane windows. It makes them unusable for ventilation. Plus I have sound deadening curtains, sound dampeners on walls, etc.
Believe me, it is loud. There is no mitigation you can do to make it not noticeable. You can only make it tolerable. The cost to get it to that level is not insignificant.
In an ideal world, housing wouldn't be built immediately on major transit lines, but a (walkable) short distance away. Alas, city planners seem dead-set that new construction must _only_ happen within a block of major roads or train lines. There seems to be a lot of urban malpractice that prevents us from making good choices.
In an ideal world, housing is built directly above transit stations, so people can get on the train without even having to go outdoors, leaving it the most obvious choice for almost all journeys.
Look at what they've achieved with this in Hong Kong. Plus the lines and stations basically pay for themselves due to revenues from residential property.
There is mitigation that can be done for the noise. However it isn't something you can do - the city would have to rebuild the tracks to modern standards.
The rain cover is really outweighed by shade/lack of sunlight. The shade tends to make the street level experience more gloomy and a significantly worse experience that people tend to avoid.
Hotter weather may change some of that but street level tends to be dark and not pleasant to be in. Like it or not, people tend to associate those areas with higher crime and the shops at street level tend to get noticeable less traffic. It depends on the size of the tracks but if you've been to the loop in Chicago or in places in NYC with elevated trains, the difference in the streets with elevated tracks and the streets without are noticeable.
Interestingly, for the suburbs here in Melbourne they offered two options for grade separation:
1. Elevated rail
2. Trenches with no cover
A series of campaigners in areas with higher property values wanted the trenches for “privacy” reasons and in the end many of them got them but the elevated rail receiving citizens got bike paths, basketball courts, car parks, improved walkability, generally more public space.
Having experienced the two, the elevated rail is far better.
The totally new line they are building though will be a TBM.
I recall from a PBS special that in the late 1800s, NYC suffered a blizzard that shut down even elevated trains for days. Hence, the move towards building underground.
Newer ones make less noise. The old steel structures in Chicago make a lot of noise. The sky train in Vancouver isn't silent, but it is not loud: they knew noise could be an issue and so built to make it not a problem.
