My first flat was a gorgeous 1950s ex-council in London. Very small estate, beautiful position, huge rooms, excellent traditional brick construction. It was a lovely place to live and I sold it for 5x what I paid. It's not true to say they don't appreciate in value, they just will always be cheap for what you get, so they'll never be worth what a private flat of same size in same location is worth- but then you won't have paid those prices in the first place.
Benefits for me of council estate was that it was well looked-after - we had a live-in caretaker in my block, communal areas were maintained and done to a schedule rather than tenants having to fight to come to an agreement. Dealing with the council for repairs was actually brilliant - for instance, once the tenant above had a leak that came in my flat, and the council sorted out repairs instantly and without quibbling, rather than if you are dealing with an individual who may not have the money to sort something quickly. Purpose built flat rather than a conversion was so nice, sensible layout, proper bathroom with window, nice big balcony for outdoor space.
Cons - As others have said Major Works are separate to the low annual service charge, and you don't really get any say about anything - timing, cost, contractors etc. But the process is very formalised and you get a lot of warning. That said, I lived in mine for 12 years without getting any bills larger than for a repaint, but I think double glazing happened shortly after I left. Other people will doubtless be a bit snobby about you living in a council flat.
The biggest problem with mine was the lease was a bit over-dramatic. I think the Labour council were a bit snippy about right-to-buy and also very keen to wash themselves of any responsibility for any structural defects, so the lease had quite a lot of stuff in it about random bits of the building that might fall apart and if it did, the council had no liability. The building was actually very solid and had no problems, but when I was selling the lease did spook some buyers, even though survey said there was nothing wrong with the building. It's sold several times since then so, possibly I just got unlucky with buyers.
Watch out for blocks with lifts - lift maintenance charges can be hugely expensive.