Maybe I shouldn't answer because housing is becoming prohibitively expensive so I shouldn't incentivize people to come here, but people have helped me in HN in the past :) So I'll do it.
In my view it's a city with awesome quality of life. Indeed it's cloudy, rainy and windy but it's better than most Galician cities (cough, Santiago, cough) and not that bad in the grand scheme of things, depends on what you compare to. 20 or 30 years ago I used to very strongly prefer the climate in southern Spain to that in Galicia, but with climate change things have changed a lot. We now have an actual summer that lasts for 3-4 months (it used to be one month, with luck :)), winters are mild, and we don't have the sweltering summer heat that is common in other parts of Spain. If you really need a lot of sun you won't like it, but if you're OK with weather being somewhat unpredictable as long as temperatures are mild (to give you an idea, we use heating for around 5 months but only turn it on like ~1 hour a day, and we don't feel there is need for AC), I'd say it's fine.
In general, pros:
- Great surroundings with coast, beaches, cliffs, the port, etc.; everything easily reachable by foot or bike from the city center (there are beaches in the city center).
- A 12 km long seafront walk (also friendly for cycling and running) with nice surroundings and sights.
- Nice size, in my opinion: big enough to have plenty of things to do, but small enough to be manageable (in Madrid in theory you have more stuff to do, but in practice my friends who live there end up going to things in their district because moving around is cumbersome. In A Coruña it's easy to get to an event anywhere in the city).
- The city is extremely safe. I have been here for 20 years and I think in all that time I only got asked for money by a junkie at 3 AM once. Nothing more serious than that ever happened to me (and I used to go clubbing night a lot, and still often take walks at night).
- Punches above its weight when it comes to events. From St John's night (23rd June) to early September there are events literally every day - concerts, book/art/medieval/comic/science fairs, exhibitions, workshops, and so on. The rest of the year not so much but still more than in other cities I know of comparable size.
- Also lots of things to do with children, if you have them. Many events specifically for them, apart from not one but three science museums plus an aquarium. And of course the above mentioned beaches.
- Like many Spanish cities, it has plenty of lively walkable streets to go shopping, for some wine/tapas, dining, etc. A lot of street life, unless in very rainy days.
- Galician food is top notch.
- While we are far from northern European levels of bicycle usage, lately there has been quite a lot of progress, with bike lanes and a bike-sharing service that works quite well.
- The city is booming right now, the economy is going well, people have work, so there is a lot of activity in general. (This may change, though. A political change in Spain is incoming and IMO it's not going to be for the better).
- You can reach other interesting cities, like Santiago or Pontevedra, by highway or even better, by train. Santiago is less than half an hour away by train and they are frequent.
So-so:
- Public transport has room for improvement, but it works. Maybe with some wait but it'll take you anywhere.
Cons:
- Still too many cars and pollution for my taste (although we're making progress). Although of course, much less than in any US city, and the city is perfectly walkable.
- The amount of dogs is absolutely insane. Honestly, I travel a lot and I haven't seen a city even close to the amount of dogs you see here. I guess it's maybe not a con if you have one :) But to me it's very annoying, because there's always people that lets them loose near children or that doesn't pick up their excrements, so finding dog poo is very common. And it's difficult not to hear some neighbor with a dog that barks.
- Construction quality tends to be bad. Most buildings are from the 60s-70s boom, ugly blocks with poor insulation. Much of the housing prior to that has little natural light and much of the housing after that has little space.
- Also related to this, the city center, tourist areas and parts of the city by the sea, etc. are beautiful; but many neighborhoods are ugly as hell, full of soulless blocks that have little to envy from Soviet architecture.
- Housing prices are skyrocketing both for buying and renting.
- Since we are in a corner of Spain, traveling tends to be inconvenient. We do have high-speed rail to Madrid which works very well, but if you want to go further, you typically need to take a flight to Madrid or Barcelona and there are not many, so layovers tend to get long.