Well, prescription vet diets for stuff like this are proven to work, and I've not heard yet of other diets that are not. So with feeding non-prescription diets you run the risk that the crystals may get worse...
Diet is important either way, but were we talking about a boy kitty, its life or death, as they have narrower urethra that can actually completely block up.
That strategy is what I choose for Oscar. I don't even think he has food allergies, but it's a case of me knowing its highly unlikely the vet diet he eats will make him worse, can't hurt, and might even help a little with his allergies.
In the end, its your choice
Honestly, the way I have always looked at it is that although the food is a little more expensive, I do not have the money to be clearing up a skin infection that might come from eating something he's allergic to. ($110 a pop per vet visit and antibiotics, plus possible other products)
I can only please one person per day. Today is not your day, tomorrow doesn't look good either.
"You didn't know of the magical powers of the break stick? It's up there with genies and Harry Potter as far as magic levels go." SisMorphine 01/07/07