Coatbridge Central doesn't rank high on my favourites list either.
There's something I quite like about CBC, particularly the underpass. You feel that the station was once an important rail hub (which it was), and there is a twinge of nostalgia in that tunnel for me on the few occasions I've boarded the 1tph currently calling there.
My favourite is probably Edinburgh Waverley, closely followed by Glasgow Central (High Level). Both grand stations with lovely architecture. They fit their roles as Scotland's most important rail stations.
However, if we were to limit it to Scotrail stations, I'd probably go with
Partick. The refurbishment was great, and when I used to commute there it was a pleasure to pass through the station. There's a lot wrong with it operationally (no toilets, one ticket window), but I like the station itself. Haymarket is also in the running, again a pretty grim station that's had a fantastic refurb. On a smaller level, Elgin is a basic but very good station, with aj ample waiting area and generally good staff.
Worst is a tough one. There are plenty of terrible stations, as has been mentioned in the SPT area in particular. I've always found
Anderston to be particularly grim. Perhaps the glimmer of daylight just makes the underground cavern seem even worse. I'm also not a great fan of Dalmarnock, I'm not convinced that the refurbishment was up to standard to be honest (at least at the platform level, it's still very grim).
I'm not sure why there's no love for Aberdeen station. It services its purpose very well in my experience, and there's a good amount of light and the connection to Union Square shopping centre for long waits. It's probably in my top 10 in Scotland actually.
