Well it may have been stunning and palatial 40 or 30 years ago, but that was in the era of Air Canada, BOAC/BA, Northwest etc, all of whom are out of Scotland, at the time giving a norm of half a million pax a year at PIK.
Now we have predominately Ryanair, nearing 3 million pax a year, and an airport and services of much more use to many more travellers. You can check-in online, get through security within minutes, try not to topple any bottles in 'duty free', and wait briefly in a not too appealing departure hall which is about to be revamped. The standing waiting in corridors is not too pleasant, but probably deliberate, probably Ryanair, policy. ie have the pax boarding the same minute the crew gives the OK. And with the maligned open seating the Ryanair cabin can be settled in 15 minutes, and some flights leave up to 15 minutes early.
See the theme, cheap and maybe not too cheerful, but efficient, and with service to around 30 destinations. eg Stockholm this year for two on business was £80 total and 2 working days each out of the office. Five years ago it was £800 and 3 days out with the legacy airlines.
So like it or lump it, even in its present form, PIK and its airlines can easily be a first choice if you accept you only get what you pay for, an efficient bus service. The people intent on posting the more colourful exaggerated descriptions of the place should perhaps wind themselves back to a little realism and acceptance , or go fly from GLA on a legacy airline. That's easy, efficient and cost effective to places like Paris, Brussels, Stockholm, and many others in Europe isn't it ?