Good:
Oslo - Nice and open, easy to navigate and no problem getting a ticket or finding the platform
York - A nice building in itself, good shops and a good railway bar
King's Cross & St Pancras - Even though they're big I've always found them easy to get around (not been for many years though so could have changed)
Bad:
Stevenedge - Utterly depressing and hopeless. Dull, grey, hard to get around, next to no facilities
Brussels - Really seedy vibe all throughout the station - lots of people just hanging around looking dodgy
Birmingham New Street - Find it really hard to navigate and if you're meeting someone it's hard to pin down a spot as you could be at completely different entrances
Oslo - Nice and open, easy to navigate and no problem getting a ticket or finding the platform
York - A nice building in itself, good shops and a good railway bar
King's Cross & St Pancras - Even though they're big I've always found them easy to get around (not been for many years though so could have changed)
Bad:
Stevenedge - Utterly depressing and hopeless. Dull, grey, hard to get around, next to no facilities
Brussels - Really seedy vibe all throughout the station - lots of people just hanging around looking dodgy
Birmingham New Street - Find it really hard to navigate and if you're meeting someone it's hard to pin down a spot as you could be at completely different entrances