What is the best dry cat food brand for a cat with irritable bowel syndrome ibs?

My cat has irritable bowel syndrome and the vet has suggested Hills dry food for sensitive cats as a way forward to combat his diarrhoea. I just wondered if anyone else had any experience with cats with IBS and what they feed them as im worried my vet may be advising that brand as its the only one they sell! Price isnt important, it just needs to be super bland! Many thanks!