i must be lucky here too - the rescue's vet prescribe them a lot, whereas my vet doesn't - when I had Tom, the rescue's vet wanted him on c/d, they gave us some samples of dry, and he still got cystitis, I had taken him to mine for a weigh in, and she told me she doesn't agree with prescription diets for urinary issues, her 'prescription' is mainly wet food, more water, less stress and possibly Cystaid - worked wonders with Tom, and it helped his weight loss, which the r/d and c/d given by the rescue's vet hadn't - plus a lot cheaper!!
The only prescription diet I personally have in is a/d, I do like that. I have been faced with cats with health issues where normally a prescription diet is given, but they hate it, so I would rather have them eat whatever, and less time with me, than be unhappy and hungry - most cats with health issues need to eat, and if they hate it to the extreme, it doesn't help, as not eating can cause health issues. And if you looked at/smelt some of them like k/d, i/d, you would know why cats dont like them!!