I have been there twice. It has McEwan's beat by a country mile. It is indeed a bright engaging store. And, yes, the prices are a bit steep-but this is its market niche.
I loved the way their Pastries are 'Signed' clearly displaying the name of each of their sources. That is something I have never seen in another similar store. They do boast a complete kitchen which is visible in the back, and offer a broad range of unusual or novel foods and treats.
You can certainly find some items that you will find at your local supermarket, but when the Rolls Royce has been valet parked, why go elsewhere?
This will be a success!