Agree that PIK's departure lounge is desperate at present. I gather that there are major plans to completely revamp it but that does not make up for the fact that toilets are not cleaned regularly and that litter is left. (Having said that I am always amazed at the litter left by passengers at all the airports I regularly fly to). As for the catering (SSP) this franchise is a rip off whichever airport they are at and I think they are based in most major UK airports. Quality is crap also and I gather they pay their staff sweet FA - hence the service - it is not just PIK.
As regards flying into Glasgow 'city' airport don't expect anything drastically different if you park at T2 - it is as bad as PIK and needs a major clean up also. Both terminals are now showing their age quite markedly.