Edinburgh has to be in contention -beautiful, grand city. Walk down the main street, lined with historic mouments, and you have an extinct volcano on your left, a castle on the hill to your right, and the sea is at your back. Outside of London it's only Liverpool that has such an expansive vista in the UK.
A world city, basically, but it's also great to live in - quite small, magnificent for bevvying, beautiful countryside right on the doorstep [used to ride into the Pentland hills in about 40 mins from the city centre], decent opportunities for work. Quite socially stratified place, which is a good or bad thing depending on your POV. I live in Manchester now and you're never more than 100 yards away from a scally in an anorak, no matter where you are. Edinburgh wasn't like that.
Drawbacks are first and foremost the SNP. If that parochial pish rises from the dead in the form of another independence vote then I'd swerve Scotland full stop.
Minor stuff like the road links are sub-standard for a major city. The sea is there but it's not very well integrated to the city - a lot of old British port cities are like this (e.g. North Liverpool). If you want easy access to the mountains proper then you're 1.5/2 hours away in Edinburgh - the highlands are amazing but there are closer places to live.