A Skoda Octavia is in a different segment entirely. If you want a decent hatchback which is relatively small you'd be looking at Golfs, A3s etc.
The Golfs are more refined than BMWs current 3 series and have better build quality.
But again it all comes down to badge. A Kia will never be a premium vehicle until it makes a spin-off premium marque and builds vehicles which are only premium.
Mercedes, BMW and Audi are starting to dilute the brand image by making cheaper and cheaper vehicles in search of sales
I can understand Merc doing it, but BMW already has MINI to do that and Audi have VW, Skoda etc.
But we're going round in circles. A premium vehicle is defined by the badge on its bonnet. It doesn't matter if you have a Mercedes or BMW but is it anything compared to a Bentley badge? Not really